Calculus Examples

$y = x + \log_{3} (x^{2} + 5)$

Step 1

Write $y = x + \log_{3} (x^{2} + 5)$ as a function.

$f (x) = x + \log_{3} (x^{2} + 5)$

Step 2

Find the second derivative.

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Step 2.1

Find the first derivative.

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Step 2.1.1

Differentiate.

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Step 2.1.1.1

By the Sum Rule, the derivative of $x + \log_{3} (x^{2} + 5)$ with respect to $x$ is $\frac{d}{d x} [x] + \frac{d}{d x} [\log_{3} (x^{2} + 5)]$ .

$\frac{d}{d x} [x] + \frac{d}{d x} [\log_{3} (x^{2} + 5)]$

Step 2.1.1.2

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$1 + \frac{d}{d x} [\log_{3} (x^{2} + 5)]$

Step 2.1.2

Evaluate $\frac{d}{d x} [\log_{3} (x^{2} + 5)]$ .

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Step 2.1.2.1

Differentiate using the chain rule, which states that $\frac{d}{d x} [f (g (x))]$ is $f' (g (x)) g' (x)$ where $f (x) = \log_{3} (x)$ and $g (x) = x^{2} + 5$ .

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Step 2.1.2.1.1

To apply the Chain Rule, set $u$ as $x^{2} + 5$ .

$1 + \frac{d}{d u} [\log_{3} (u)] \frac{d}{d x} [x^{2} + 5]$

Step 2.1.2.1.2

The derivative of $\log_{3} (u)$ with respect to $u$ is $\frac{1}{u \ln (3)}$ .

$1 + \frac{1}{u \ln (3)} \frac{d}{d x} [x^{2} + 5]$

Step 2.1.2.1.3

Replace all occurrences of $u$ with $x^{2} + 5$ .

$1 + \frac{1}{(x^{2} + 5) \ln (3)} \frac{d}{d x} [x^{2} + 5]$

Step 2.1.2.2

By the Sum Rule, the derivative of $x^{2} + 5$ with respect to $x$ is $\frac{d}{d x} [x^{2}] + \frac{d}{d x} [5]$ .

$1 + \frac{1}{(x^{2} + 5) \ln (3)} (\frac{d}{d x} [x^{2}] + \frac{d}{d x} [5])$

Step 2.1.2.3

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 2$ .

$1 + \frac{1}{(x^{2} + 5) \ln (3)} (2 x + \frac{d}{d x} [5])$

Step 2.1.2.4

Since $5$ is constant with respect to $x$ , the derivative of $5$ with respect to $x$ is $0$ .

$1 + \frac{1}{(x^{2} + 5) \ln (3)} (2 x + 0)$

Step 2.1.2.5

Add $2 x$ and $0$ .

$1 + \frac{1}{(x^{2} + 5) \ln (3)} (2 x)$

Step 2.1.2.6

Combine $2$ and $\frac{1}{(x^{2} + 5) \ln (3)}$ .

$1 + \frac{2}{(x^{2} + 5) \ln (3)} x$

Step 2.1.2.7

Combine $\frac{2}{(x^{2} + 5) \ln (3)}$ and $x$ .

$1 + \frac{2 x}{(x^{2} + 5) \ln (3)}$

Step 2.1.3

Simplify.

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Step 2.1.3.1

Apply the distributive property.

$1 + \frac{2 x}{x^{2} \ln (3) + 5 \ln (3)}$

Step 2.1.3.2

Combine terms.

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Step 2.1.3.2.1

Write $1$ as a fraction with a common denominator.

$\frac{x^{2} \ln (3) + 5 \ln (3)}{x^{2} \ln (3) + 5 \ln (3)} + \frac{2 x}{x^{2} \ln (3) + 5 \ln (3)}$

Step 2.1.3.2.2

Combine the numerators over the common denominator.

$\frac{x^{2} \ln (3) + 5 \ln (3) + 2 x}{x^{2} \ln (3) + 5 \ln (3)}$

Step 2.1.3.3

Reorder terms.

$f' (x) = \frac{x^{2} \ln (3) + 2 x + 5 \ln (3)}{x^{2} \ln (3) + 5 \ln (3)}$

Step 2.2

Find the second derivative.

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Step 2.2.1

Differentiate using the Quotient Rule which states that $\frac{d}{d x} [\frac{f (x)}{g (x)}]$ is $\frac{g (x) \frac{d}{d x} [f (x)] - f (x) \frac{d}{d x} [g (x)]}{{g (x)}^{2}}$ where $f (x) = x^{2} \ln (3) + 2 x + 5 \ln (3)$ and $g (x) = x^{2} \ln (3) + 5 \ln (3)$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 2 x + 5 \ln (3)] - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2

Differentiate.

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Step 2.2.2.1

By the Sum Rule, the derivative of $x^{2} \ln (3) + 2 x + 5 \ln (3)$ with respect to $x$ is $\frac{d}{d x} [x^{2} \ln (3)] + \frac{d}{d x} [2 x] + \frac{d}{d x} [5 \ln (3)]$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (\frac{d}{d x} [x^{2} \ln (3)] + \frac{d}{d x} [2 x] + \frac{d}{d x} [5 \ln (3)]) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.2

Since $\ln (3)$ is constant with respect to $x$ , the derivative of $x^{2} \ln (3)$ with respect to $x$ is $\ln (3) \frac{d}{d x} [x^{2}]$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (\ln (3) \frac{d}{d x} [x^{2}] + \frac{d}{d x} [2 x] + \frac{d}{d x} [5 \ln (3)]) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.3

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 2$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (\ln (3) (2 x) + \frac{d}{d x} [2 x] + \frac{d}{d x} [5 \ln (3)]) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.4

Move $2$ to the left of $\ln (3)$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \cdot \ln (3) x + \frac{d}{d x} [2 x] + \frac{d}{d x} [5 \ln (3)]) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.5

Since $2$ is constant with respect to $x$ , the derivative of $2 x$ with respect to $x$ is $2 \frac{d}{d x} [x]$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2 \frac{d}{d x} [x] + \frac{d}{d x} [5 \ln (3)]) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.6

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2 \cdot 1 + \frac{d}{d x} [5 \ln (3)]) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.7

Multiply $2$ by $1$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2 + \frac{d}{d x} [5 \ln (3)]) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.8

Since $5 \ln (3)$ is constant with respect to $x$ , the derivative of $5 \ln (3)$ with respect to $x$ is $0$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2 + 0) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.9

Add $2 \ln (3) x + 2$ and $0$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) \frac{d}{d x} [x^{2} \ln (3) + 5 \ln (3)]}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.10

By the Sum Rule, the derivative of $x^{2} \ln (3) + 5 \ln (3)$ with respect to $x$ is $\frac{d}{d x} [x^{2} \ln (3)] + \frac{d}{d x} [5 \ln (3)]$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) (\frac{d}{d x} [x^{2} \ln (3)] + \frac{d}{d x} [5 \ln (3)])}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.11

Since $\ln (3)$ is constant with respect to $x$ , the derivative of $x^{2} \ln (3)$ with respect to $x$ is $\ln (3) \frac{d}{d x} [x^{2}]$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) (\ln (3) \frac{d}{d x} [x^{2}] + \frac{d}{d x} [5 \ln (3)])}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.12

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 2$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) (\ln (3) (2 x) + \frac{d}{d x} [5 \ln (3)])}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.13

Move $2$ to the left of $\ln (3)$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) (2 \cdot \ln (3) x + \frac{d}{d x} [5 \ln (3)])}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.14

Since $5 \ln (3)$ is constant with respect to $x$ , the derivative of $5 \ln (3)$ with respect to $x$ is $0$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) (2 \ln (3) x + 0)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.15

Simplify the expression.

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Step 2.2.2.15.1

Add $2 \ln (3) x$ and $0$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - (x^{2} \ln (3) + 2 x + 5 \ln (3)) (2 \ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.2.15.2

Multiply $2$ by $- 1$ .

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - 2 (x^{2} \ln (3) + 2 x + 5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3

Simplify.

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Step 2.2.3.1

Apply the distributive property.

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) + (- 2 (x^{2} \ln (3)) - 2 (2 x) - 2 (5 \ln (3))) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.2

Apply the distributive property.

$\frac{(x^{2} \ln (3) + 5 \ln (3)) (2 \ln (3) x + 2) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3

Simplify the numerator.

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Step 2.2.3.3.1

Simplify each term.

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Step 2.2.3.3.1.1

Simplify each term.

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Step 2.2.3.3.1.1.1

Simplify $5 \ln (3)$ by moving $5$ inside the logarithm.

$\frac{(x^{2} \ln (3) + \ln (3^{5})) (2 \ln (3) x + 2) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.1.2

Raise $3$ to the power of $5$ .

$\frac{(x^{2} \ln (3) + \ln (243)) (2 \ln (3) x + 2) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.2

Simplify each term.

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Step 2.2.3.3.1.2.1

Simplify $2 \ln (3)$ by moving $2$ inside the logarithm.

$\frac{(x^{2} \ln (3) + \ln (243)) (\ln (3^{2}) x + 2) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.2.2

Raise $3$ to the power of $2$ .

$\frac{(x^{2} \ln (3) + \ln (243)) (\ln (9) x + 2) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.3

Expand $(x^{2} \ln (3) + \ln (243)) (\ln (9) x + 2)$ using the FOIL Method.

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Step 2.2.3.3.1.3.1

Apply the distributive property.

$\frac{x^{2} \ln (3) (\ln (9) x + 2) + \ln (243) (\ln (9) x + 2) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.3.2

Apply the distributive property.

$\frac{x^{2} \ln (3) (\ln (9) x) + x^{2} \ln (3) \cdot 2 + \ln (243) (\ln (9) x + 2) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.3.3

Apply the distributive property.

$\frac{x^{2} \ln (3) (\ln (9) x) + x^{2} \ln (3) \cdot 2 + \ln (243) (\ln (9) x) + \ln (243) \cdot 2 - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4

Simplify each term.

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Step 2.2.3.3.1.4.1

Multiply $x^{2}$ by $x$ by adding the exponents.

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Step 2.2.3.3.1.4.1.1

Move $x$ .

$\frac{x \cdot x^{2} \ln (3) \ln (9) + x^{2} \ln (3) \cdot 2 + \ln (243) (\ln (9) x) + \ln (243) \cdot 2 - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.1.2

Multiply $x$ by $x^{2}$ .

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Step 2.2.3.3.1.4.1.2.1

Raise $x$ to the power of $1$ .

$\frac{x^{1} x^{2} \ln (3) \ln (9) + x^{2} \ln (3) \cdot 2 + \ln (243) (\ln (9) x) + \ln (243) \cdot 2 - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.1.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{x^{1 + 2} \ln (3) \ln (9) + x^{2} \ln (3) \cdot 2 + \ln (243) (\ln (9) x) + \ln (243) \cdot 2 - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.1.3

Add $1$ and $2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (3) \cdot 2 + \ln (243) (\ln (9) x) + \ln (243) \cdot 2 - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.2

Simplify $2 \ln (3)$ by moving $2$ inside the logarithm.

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (3^{2}) + \ln (243) (\ln (9) x) + \ln (243) \cdot 2 - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.3

Raise $3$ to the power of $2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) (\ln (9) x) + \ln (243) \cdot 2 - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.4

Multiply $\ln (243) \cdot 2$ .

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Step 2.2.3.3.1.4.4.1

Reorder $\ln (243)$ and $2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + 2 \cdot \ln (243) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.4.2

Simplify $2 \cdot \ln (243)$ by moving $2$ inside the logarithm.

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (243^{2}) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.4.5

Raise $243$ to the power of $2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) - 2 (x^{2} \ln (3)) (\ln (3) x) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.5

Multiply $x^{2}$ by $x$ by adding the exponents.

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Step 2.2.3.3.1.5.1

Move $x$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) - 2 (x \cdot x^{2} \ln (3)) \ln (3) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.5.2

Multiply $x$ by $x^{2}$ .

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Step 2.2.3.3.1.5.2.1

Raise $x$ to the power of $1$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) - 2 (x^{1} x^{2} \ln (3)) \ln (3) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.5.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) - 2 (x^{1 + 2} \ln (3)) \ln (3) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.5.3

Add $1$ and $2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) - 2 (x^{3} \ln (3)) \ln (3) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.6

Simplify $- 2 \ln (3)$ by moving $2$ inside the logarithm.

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (3^{2})) \ln (3) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.7

Raise $3$ to the power of $2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) - 2 (2 x) (\ln (3) x) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.8

Multiply $x$ by $x$ by adding the exponents.

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Step 2.2.3.3.1.8.1

Move $x$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) - 2 (2 (x \cdot x)) \ln (3) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.8.2

Multiply $x$ by $x$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) - 2 (2 x^{2}) \ln (3) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.9

Multiply $2$ by $- 2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) - 4 x^{2} \ln (3) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.10

Simplify $- 4 \ln (3)$ by moving $4$ inside the logarithm.

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) + x^{2} (- \ln (3^{4})) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.11

Raise $3$ to the power of $4$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) + x^{2} (- \ln (81)) - 2 (5 \ln (3)) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.12

Simplify $5 \ln (3)$ by moving $5$ inside the logarithm.

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) + x^{2} (- \ln (81)) - 2 \ln (3^{5}) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.13

Raise $3$ to the power of $5$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) + x^{2} (- \ln (81)) - 2 \ln (243) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.14

Simplify $- 2 \ln (243)$ by moving $2$ inside the logarithm.

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) + x^{2} (- \ln (81)) - \ln (243^{2}) (\ln (3) x)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.1.15

Raise $243$ to the power of $2$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) + x^{2} (- \ln (81)) - \ln (59049) \ln (3) x}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.2

Combine the opposite terms in $x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{3} (- \ln (9)) \ln (3) + x^{2} (- \ln (81)) - \ln (59049) \ln (3) x$ .

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Step 2.2.3.3.2.1

Reorder the factors in the terms $x^{3} \ln (3) \ln (9)$ and $x^{3} (- \ln (9)) \ln (3)$ .

$\frac{x^{3} \ln (3) \ln (9) + x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) - x^{3} \ln (3) \ln (9) + x^{2} (- \ln (81)) - \ln (59049) \ln (3) x}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.2.2

Subtract $x^{3} \ln (3) \ln (9)$ from $x^{3} \ln (3) \ln (9)$ .

$\frac{x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + 0 + x^{2} (- \ln (81)) - \ln (59049) \ln (3) x}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.2.3

Add $x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049)$ and $0$ .

$\frac{x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{2} (- \ln (81)) - \ln (59049) \ln (3) x}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.3.3

Reorder factors in $x^{2} \ln (9) + \ln (243) \ln (9) x + \ln (59049) + x^{2} (- \ln (81)) - \ln (59049) \ln (3) x$ .

$\frac{x^{2} \ln (9) + x \ln (243) \ln (9) + \ln (59049) - x^{2} \ln (81) - x \ln (59049) \ln (3)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.2.3.4

Reorder terms.

$f'' (x) = \frac{x^{2} \ln (9) + x \ln (243) \ln (9) - x^{2} \ln (81) - x \ln (3) \ln (59049) + \ln (59049)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 2.3

The second derivative of $f (x)$ with respect to $x$ is $\frac{x^{2} \ln (9) + x \ln (243) \ln (9) - x^{2} \ln (81) - x \ln (3) \ln (59049) + \ln (59049)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$ .

$\frac{x^{2} \ln (9) + x \ln (243) \ln (9) - x^{2} \ln (81) - x \ln (3) \ln (59049) + \ln (59049)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 3

Set the second derivative equal to $0$ then solve the equation $\frac{x^{2} \ln (9) + x \ln (243) \ln (9) - x^{2} \ln (81) - x \ln (3) \ln (59049) + \ln (59049)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}} = 0$ .

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Step 3.1

Set the second derivative equal to $0$ .

$\frac{x^{2} \ln (9) + x \ln (243) \ln (9) - x^{2} \ln (81) - x \ln (3) \ln (59049) + \ln (59049)}{{(x^{2} \ln (3) + 5 \ln (3))}^{2}} = 0$

Step 3.2

Set the numerator equal to zero.

$x^{2} \ln (9) + x \ln (243) \ln (9) - x^{2} \ln (81) - x \ln (3) \ln (59049) + \ln (59049) = 0$

Step 3.3

Solve the equation for $x$ .

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Step 3.3.1

Move $x \ln (243) \ln (9)$ .

$x^{2} \ln (9) - x^{2} \ln (81) + x \ln (243) \ln (9) - x \ln (3) \ln (59049) + \ln (59049) = 0$

Step 3.3.2

Use the quadratic formula to find the solutions.

$\frac{- b \pm \sqrt{b^{2} - 4 (a c)}}{2 a}$

Step 3.3.3

Substitute the values $a = \ln (9) - \ln (81)$ , $b = \ln (243) \ln (9) - \ln (3) \ln (59049)$ , and $c = \ln (59049)$ into the quadratic formula and solve for $x$ .

$\frac{- (\ln (243) \ln (9) - \ln (3) \ln (59049)) \pm \sqrt{{(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2} - 4 \cdot ((\ln (9) - \ln (81)) \cdot \ln (59049))}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4

Simplify the numerator.

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Step 3.3.4.1

Apply the distributive property.

$x = \frac{- (\ln (243) \ln (9)) - (- \ln (3) \ln (59049)) \pm \sqrt{{(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2} - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.2

Multiply $- (- \ln (3) \ln (59049))$ .

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Step 3.3.4.2.1

Multiply $- 1$ by $- 1$ .

$x = \frac{- \ln (243) \ln (9) + 1 (\ln (3) \ln (59049)) \pm \sqrt{{(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2} - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.2.2

Multiply $\ln (3)$ by $1$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{{(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2} - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.3

Rewrite ${(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2}$ as $(\ln (243) \ln (9) - \ln (3) \ln (59049)) (\ln (243) \ln (9) - \ln (3) \ln (59049))$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{(\ln (243) \ln (9) - \ln (3) \ln (59049)) (\ln (243) \ln (9) - \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.4

Expand $(\ln (243) \ln (9) - \ln (3) \ln (59049)) (\ln (243) \ln (9) - \ln (3) \ln (59049))$ using the FOIL Method.

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Step 3.3.4.4.1

Apply the distributive property.

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln (243) \ln (9) (\ln (243) \ln (9) - \ln (3) \ln (59049)) - \ln (3) \ln (59049) (\ln (243) \ln (9) - \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.4.2

Apply the distributive property.

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln (243) \ln (9) (\ln (243) \ln (9)) + \ln (243) \ln (9) (- \ln (3) \ln (59049)) - \ln (3) \ln (59049) (\ln (243) \ln (9) - \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.4.3

Apply the distributive property.

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln (243) \ln (9) (\ln (243) \ln (9)) + \ln (243) \ln (9) (- \ln (3) \ln (59049)) - \ln (3) \ln (59049) (\ln (243) \ln (9)) - \ln (3) \ln (59049) (- \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5

Simplify and combine like terms.

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Step 3.3.4.5.1

Simplify each term.

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Step 3.3.4.5.1.1

Multiply $\ln (243)$ by $\ln (243)$ by adding the exponents.

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Step 3.3.4.5.1.1.1

Move $\ln (243)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln (243) \ln (243) \ln (9) \ln (9) + \ln (243) \ln (9) (- \ln (3) \ln (59049)) - \ln (3) \ln (59049) (\ln (243) \ln (9)) - \ln (3) \ln (59049) (- \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.1.2

Multiply $\ln (243)$ by $\ln (243)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln (9) \ln (9) + \ln (243) \ln (9) (- \ln (3) \ln (59049)) - \ln (3) \ln (59049) (\ln (243) \ln (9)) - \ln (3) \ln (59049) (- \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.2

Multiply $\ln (9)$ by $\ln (9)$ by adding the exponents.

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Step 3.3.4.5.1.2.1

Move $\ln (9)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) (\ln (9) \ln (9)) + \ln (243) \ln (9) (- \ln (3) \ln (59049)) - \ln (3) \ln (59049) (\ln (243) \ln (9)) - \ln (3) \ln (59049) (- \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.2.2

Multiply $\ln (9)$ by $\ln (9)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) + \ln (243) \ln (9) (- \ln (3) \ln (59049)) - \ln (3) \ln (59049) (\ln (243) \ln (9)) - \ln (3) \ln (59049) (- \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.3

Rewrite using the commutative property of multiplication.

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (243) \ln (9) \ln (3) \ln (59049) - \ln (3) \ln (59049) (\ln (243) \ln (9)) - \ln (3) \ln (59049) (- \ln (3) \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.4

Multiply $\ln (3)$ by $\ln (3)$ by adding the exponents.

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Step 3.3.4.5.1.4.1

Move $\ln (3)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (243) \ln (9) \ln (3) \ln (59049) - \ln (3) \ln (59049) \ln (243) \ln (9) - \ln (3) \ln (3) \ln (59049) (- 1 \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.4.2

Multiply $\ln (3)$ by $\ln (3)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (243) \ln (9) \ln (3) \ln (59049) - \ln (3) \ln (59049) \ln (243) \ln (9) - \ln^{2} (3) \ln (59049) (- 1 \ln (59049)) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.5

Multiply $\ln (59049)$ by $\ln (59049)$ by adding the exponents.

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Step 3.3.4.5.1.5.1

Move $\ln (59049)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (243) \ln (9) \ln (3) \ln (59049) - \ln (3) \ln (59049) \ln (243) \ln (9) - \ln^{2} (3) (\ln (59049) \ln (59049)) \cdot - 1 - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.5.2

Multiply $\ln (59049)$ by $\ln (59049)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (243) \ln (9) \ln (3) \ln (59049) - \ln (3) \ln (59049) \ln (243) \ln (9) - \ln^{2} (3) \ln^{2} (59049) \cdot - 1 - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.6

Multiply $- \ln^{2} (3) \ln^{2} (59049) \cdot - 1$ .

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Step 3.3.4.5.1.6.1

Multiply $- 1$ by $- 1$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (243) \ln (9) \ln (3) \ln (59049) - \ln (3) \ln (59049) \ln (243) \ln (9) + 1 \ln^{2} (3) \ln^{2} (59049) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.1.6.2

Multiply $\ln^{2} (3)$ by $1$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (243) \ln (9) \ln (3) \ln (59049) - \ln (3) \ln (59049) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.2

Move $\ln (3)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - \ln (59049) \ln (3) \ln (243) \ln (9) - 1 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.5.3

Subtract $\ln (59049) \ln (3) \ln (243) \ln (9)$ from $- \ln (59049) \ln (3) \ln (243) \ln (9)$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.6

Apply the distributive property.

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) + (- 4 \ln (9) - 4 (- \ln (81))) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.7

Multiply $- 1$ by $- 4$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) + (- 4 \ln (9) + 4 \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.4.8

Apply the distributive property.

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.5

Simplify the expression to solve for the $+$ portion of the $\pm$ .

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Step 3.3.5.1

Change the $\pm$ to $+$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.5.2

Factor $- 1$ out of $- \ln (243) \ln (9)$ .

$x = \frac{- (\ln (243) \ln (9)) + \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.5.3

Factor $- 1$ out of $\ln (3) \ln (59049)$ .

$x = \frac{- (\ln (243) \ln (9)) - (- \ln (3) \ln (59049)) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.5.4

Factor $- 1$ out of $- (\ln (243) \ln (9)) - (- \ln (3) \ln (59049))$ .

$x = \frac{- (\ln (243) \ln (9) - \ln (3) \ln (59049)) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.5.5

Factor $- 1$ out of $\sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}$ .

$x = \frac{- (\ln (243) \ln (9) - \ln (3) \ln (59049)) - 1 (- \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})}{2 (\ln (9) - \ln (81))}$

Step 3.3.5.6

Factor $- 1$ out of $- (\ln (243) \ln (9) - \ln (3) \ln (59049)) - 1 (- \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})$ .

$x = \frac{- (\ln (243) \ln (9) - \ln (3) \ln (59049) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})}{2 (\ln (9) - \ln (81))}$

Step 3.3.5.7

Rewrite $- (\ln (243) \ln (9) - \ln (3) \ln (59049) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})$ as $- 1 (\ln (243) \ln (9) - \ln (3) \ln (59049) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})$ .

$x = \frac{- 1 (\ln (243) \ln (9) - \ln (3) \ln (59049) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})}{2 (\ln (9) - \ln (81))}$

Step 3.3.5.8

Move the negative in front of the fraction.

Step 3.3.6

Simplify the expression to solve for the $-$ portion of the $\pm$ .

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Step 3.3.6.1

Simplify the numerator.

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Step 3.3.6.1.1

Apply the distributive property.

$x = \frac{- (\ln (243) \ln (9)) - (- \ln (3) \ln (59049)) \pm \sqrt{{(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2} - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.1.2

Multiply $- (- \ln (3) \ln (59049))$ .

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Step 3.3.6.1.2.1

Multiply $- 1$ by $- 1$ .

$x = \frac{- \ln (243) \ln (9) + 1 (\ln (3) \ln (59049)) \pm \sqrt{{(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2} - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.1.2.2

Multiply $\ln (3)$ by $1$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) \pm \sqrt{{(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2} - 4 \cdot (\ln (9) - \ln (81)) \cdot \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.1.3

Rewrite ${(\ln (243) \ln (9) - \ln (3) \ln (59049))}^{2}$ as $(\ln (243) \ln (9) - \ln (3) \ln (59049)) (\ln (243) \ln (9) - \ln (3) \ln (59049))$ .

Step 3.3.6.1.4

Expand $(\ln (243) \ln (9) - \ln (3) \ln (59049)) (\ln (243) \ln (9) - \ln (3) \ln (59049))$ using the FOIL Method.

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Step 3.3.6.1.4.1

Apply the distributive property.

Step 3.3.6.1.4.2

Apply the distributive property.

Step 3.3.6.1.4.3

Apply the distributive property.

Step 3.3.6.1.5

Simplify and combine like terms.

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Step 3.3.6.1.5.1

Simplify each term.

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Step 3.3.6.1.5.1.1

Multiply $\ln (243)$ by $\ln (243)$ by adding the exponents.

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Step 3.3.6.1.5.1.1.1

Move $\ln (243)$ .

Step 3.3.6.1.5.1.1.2

Multiply $\ln (243)$ by $\ln (243)$ .

Step 3.3.6.1.5.1.2

Multiply $\ln (9)$ by $\ln (9)$ by adding the exponents.

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Step 3.3.6.1.5.1.2.1

Move $\ln (9)$ .

Step 3.3.6.1.5.1.2.2

Multiply $\ln (9)$ by $\ln (9)$ .

Step 3.3.6.1.5.1.3

Rewrite using the commutative property of multiplication.

Step 3.3.6.1.5.1.4

Multiply $\ln (3)$ by $\ln (3)$ by adding the exponents.

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Step 3.3.6.1.5.1.4.1

Move $\ln (3)$ .

Step 3.3.6.1.5.1.4.2

Multiply $\ln (3)$ by $\ln (3)$ .

Step 3.3.6.1.5.1.5

Multiply $\ln (59049)$ by $\ln (59049)$ by adding the exponents.

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Step 3.3.6.1.5.1.5.1

Move $\ln (59049)$ .

Step 3.3.6.1.5.1.5.2

Multiply $\ln (59049)$ by $\ln (59049)$ .

Step 3.3.6.1.5.1.6

Multiply $- \ln^{2} (3) \ln^{2} (59049) \cdot - 1$ .

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Step 3.3.6.1.5.1.6.1

Multiply $- 1$ by $- 1$ .

Step 3.3.6.1.5.1.6.2

Multiply $\ln^{2} (3)$ by $1$ .

Step 3.3.6.1.5.2

Move $\ln (3)$ .

Step 3.3.6.1.5.3

Subtract $\ln (59049) \ln (3) \ln (243) \ln (9)$ from $- \ln (59049) \ln (3) \ln (243) \ln (9)$ .

Step 3.3.6.1.6

Apply the distributive property.

Step 3.3.6.1.7

Multiply $- 1$ by $- 4$ .

Step 3.3.6.1.8

Apply the distributive property.

Step 3.3.6.2

Change the $\pm$ to $-$ .

$x = \frac{- \ln (243) \ln (9) + \ln (3) \ln (59049) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.3

Factor $- 1$ out of $- \ln (243) \ln (9)$ .

$x = \frac{- (\ln (243) \ln (9)) + \ln (3) \ln (59049) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.4

Factor $- 1$ out of $\ln (3) \ln (59049)$ .

$x = \frac{- (\ln (243) \ln (9)) - (- \ln (3) \ln (59049)) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.5

Factor $- 1$ out of $- (\ln (243) \ln (9)) - (- \ln (3) \ln (59049))$ .

$x = \frac{- (\ln (243) \ln (9) - \ln (3) \ln (59049)) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.6

Factor $- 1$ out of $- \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}$ .

Step 3.3.6.7

Factor $- 1$ out of $- (\ln (243) \ln (9) - \ln (3) \ln (59049)) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}$ .

$x = \frac{- (\ln (243) \ln (9) - \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.8

Rewrite $- (\ln (243) \ln (9) - \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})$ as $- 1 (\ln (243) \ln (9) - \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})$ .

$x = \frac{- 1 (\ln (243) \ln (9) - \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)})}{2 (\ln (9) - \ln (81))}$

Step 3.3.6.9

Move the negative in front of the fraction.

$x = - \frac{\ln (243) \ln (9) - \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 3.3.7

The final answer is the combination of both solutions.

$x = - \frac{\ln (243) \ln (9) - \ln (3) \ln (59049) - \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}, - \frac{\ln (243) \ln (9) - \ln (3) \ln (59049) + \sqrt{\ln^{2} (243) \ln^{2} (9) - 2 \ln (59049) \ln (3) \ln (243) \ln (9) + \ln^{2} (3) \ln^{2} (59049) - 4 \ln (9) \ln (59049) + 4 \ln (81) \ln (59049)}}{2 (\ln (9) - \ln (81))}$

Step 4

Find the points where the second derivative is $0$ .

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Step 4.1

Substitute $- 2.23606797$ in $f (x) = x + \log_{3} (x^{2} + 5)$ to find the value of $y$ .

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Step 4.1.1

Replace the variable $x$ with $- 2.23606797$ in the expression.

$f (- 2.23606797) = (- 2.23606797) + \log_{3} ({(- 2.23606797)}^{2} + 5)$

Step 4.1.2

Simplify the result.

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Step 4.1.2.1

Simplify each term.

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Step 4.1.2.1.1

Raise $- 2.23606797$ to the power of $2$ .

$f (- 2.23606797) = - 2.23606797 + \log_{3} (5 + 5)$

Step 4.1.2.1.2

Add $5$ and $5$ .

$f (- 2.23606797) = - 2.23606797 + \log_{3} (10)$

Step 4.1.2.1.3

Log base $3$ of $10$ is approximately $2.09590327$ .

$f (- 2.23606797) = - 2.23606797 + 2.09590327$

Step 4.1.2.2

Add $- 2.23606797$ and $2.09590327$ .

$f (- 2.23606797) = - 0.1401647$

Step 4.1.2.3

The final answer is $- 0.1401647$ .

$- 0.1401647$

Step 4.2

The point found by substituting $- 2.23606797$ in $f (x) = x + \log_{3} (x^{2} + 5)$ is $(- 2.23606797, - 0.1401647)$ . This point can be an inflection point.

$(- 2.23606797, - 0.1401647)$

Step 4.3

Substitute $2.23606797$ in $f (x) = x + \log_{3} (x^{2} + 5)$ to find the value of $y$ .

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Step 4.3.1

Replace the variable $x$ with $2.23606797$ in the expression.

$f (2.23606797) = (2.23606797) + \log_{3} ({(2.23606797)}^{2} + 5)$

Step 4.3.2

Simplify the result.

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Step 4.3.2.1

Simplify each term.

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Step 4.3.2.1.1

Raise $2.23606797$ to the power of $2$ .

$f (2.23606797) = 2.23606797 + \log_{3} (5 + 5)$

Step 4.3.2.1.2

Add $5$ and $5$ .

$f (2.23606797) = 2.23606797 + \log_{3} (10)$

Step 4.3.2.1.3

Log base $3$ of $10$ is approximately $2.09590327$ .

$f (2.23606797) = 2.23606797 + 2.09590327$

Step 4.3.2.2

Add $2.23606797$ and $2.09590327$ .

$f (2.23606797) = 4.33197125$

Step 4.3.2.3

The final answer is $4.33197125$ .

$4.33197125$

Step 4.4

The point found by substituting $2.23606797$ in $f (x) = x + \log_{3} (x^{2} + 5)$ is $(2.23606797, 4.33197125)$ . This point can be an inflection point.

$(2.23606797, 4.33197125)$

Step 4.5

Determine the points that could be inflection points.

$(- 2.23606797, - 0.1401647), (2.23606797, 4.33197125)$

Step 5

Split $(- \infty, \infty)$ into intervals around the points that could potentially be inflection points.

$(- \infty, - 2.23606797) \cup (- 2.23606797, 2.23606797) \cup (2.23606797, \infty)$

Step 6

Substitute a value from the interval $(- \infty, - 2.23606797)$ into the second derivative to determine if it is increasing or decreasing.

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Step 6.1

Replace the variable $x$ with $- 2.33606797$ in the expression.

$f'' (- 2.33606797) = \frac{{(- 2.33606797)}^{2} \ln (9) + (- 2.33606797) \ln (243) \ln (9) - {(- 2.33606797)}^{2} \ln (81) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2

Simplify the result.

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Step 6.2.1

Simplify the numerator.

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Step 6.2.1.1

Raise $- 2.33606797$ to the power of $2$ .

$f'' (- 2.33606797) = \frac{5.45721359 \ln (9) - 2.33606797 \ln (243) \ln (9) - {(- 2.33606797)}^{2} \ln (81) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.2

Simplify $5.45721359 \ln (9)$ by moving $5.45721359$ inside the logarithm.

$f'' (- 2.33606797) = \frac{\ln (9^{5.45721359}) - 2.33606797 \ln (243) \ln (9) - {(- 2.33606797)}^{2} \ln (81) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.3

Raise $9$ to the power of $5.45721359$ .

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - 2.33606797 \ln (243) \ln (9) - {(- 2.33606797)}^{2} \ln (81) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.4

Simplify $- 2.33606797 \ln (243)$ by moving $2.33606797$ inside the logarithm.

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - \ln (243^{2.33606797}) \ln (9) - {(- 2.33606797)}^{2} \ln (81) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.5

Raise $243$ to the power of $2.33606797$ .

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - \ln (374057.54800345) \ln (9) - {(- 2.33606797)}^{2} \ln (81) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.6

Raise $- 2.33606797$ to the power of $2$ .

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - \ln (374057.54800345) \ln (9) - 1 \cdot (5.45721359 \ln (81)) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.7

Multiply $- 1$ by $5.45721359$ .

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - \ln (374057.54800345) \ln (9) - 5.45721359 \ln (81) + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.8

Multiply $- 5.45721359$ by $\ln (81)$ .

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - \ln (374057.54800345) \ln (9) - 23.98144767 + 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.9

Simplify $2.33606797 \ln (3)$ by moving $2.33606797$ inside the logarithm.

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - \ln (374057.54800345) \ln (9) - 23.98144767 + \ln (3^{2.33606797}) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.10

Raise $3$ to the power of $2.33606797$ .

$f'' (- 2.33606797) = \frac{\ln (161252.03194789) - \ln (374057.54800345) \ln (9) - 23.98144767 + \ln (13.0193015) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.11

Subtract $23.98144767$ from $\ln (161252.03194789)$ .

$f'' (- 2.33606797) = \frac{- \ln (374057.54800345) \ln (9) - 11.99072383 + \ln (13.0193015) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.12

Subtract $11.99072383$ from $- \ln (374057.54800345) \ln (9)$ .

$f'' (- 2.33606797) = \frac{- 40.18587201 + \ln (13.0193015) \ln (59049) + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.13

Add $- 40.18587201$ and $\ln (13.0193015) \ln (59049)$ .

$f'' (- 2.33606797) = \frac{- 11.99072383 + \ln (59049)}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.1.14

Add $- 11.99072383$ and $\ln (59049)$ .

$f'' (- 2.33606797) = \frac{- 1.00460094}{{({(- 2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.2

Simplify the denominator.

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Step 6.2.2.1

Raise $- 2.33606797$ to the power of $2$ .

$f'' (- 2.33606797) = \frac{- 1.00460094}{{(5.45721359 \ln (3) + 5 \ln (3))}^{2}}$

Step 6.2.2.2

Simplify $5.45721359 \ln (3)$ by moving $5.45721359$ inside the logarithm.

$f'' (- 2.33606797) = \frac{- 1.00460094}{{(\ln (3^{5.45721359}) + 5 \ln (3))}^{2}}$

Step 6.2.2.3

Raise $3$ to the power of $5.45721359$ .

$f'' (- 2.33606797) = \frac{- 1.00460094}{{(\ln (401.56199016) + 5 \ln (3))}^{2}}$

Step 6.2.2.4

Simplify $5 \ln (3)$ by moving $5$ inside the logarithm.

$f'' (- 2.33606797) = \frac{- 1.00460094}{{(\ln (401.56199016) + \ln (3^{5}))}^{2}}$

Step 6.2.2.5

Raise $3$ to the power of $5$ .

$f'' (- 2.33606797) = \frac{- 1.00460094}{{(\ln (401.56199016) + \ln (243))}^{2}}$

Step 6.2.2.6

Use the product property of logarithms, $\log_{b} (x) + \log_{b} (y) = \log_{b} (x y)$ .

$f'' (- 2.33606797) = \frac{- 1.00460094}{\ln^{2} (401.56199016 \cdot 243)}$

Step 6.2.2.7

Multiply $401.56199016$ by $243$ .

$f'' (- 2.33606797) = \frac{- 1.00460094}{\ln^{2} (97579.56361088)}$

Step 6.2.3

Move the negative in front of the fraction.

$f'' (- 2.33606797) = - \frac{1.00460094}{\ln^{2} (97579.56361088)}$

Step 6.2.4

Replace $e$ with an approximation.

$f'' (- 2.33606797) = - \frac{1.00460094}{{\log_{2.71828182}}^{2} (97579.56361088)}$

Step 6.2.5

Log base $2.71828182$ of $97579.56361088$ is approximately $11.48842336$ .

$f'' (- 2.33606797) = - \frac{1.00460094}{{11.48842336}^{2}}$

Step 6.2.6

Raise $11.48842336$ to the power of $2$ .

$f'' (- 2.33606797) = - \frac{1.00460094}{131.98387132}$

Step 6.2.7

Divide $1.00460094$ by $131.98387132$ .

$f'' (- 2.33606797) = - 1 \cdot 0.00761154$

Step 6.2.8

Multiply $- 1$ by $0.00761154$ .

$f'' (- 2.33606797) = - 0.00761154$

Step 6.2.9

The final answer is $- 0.00761154$ .

$- 0.00761154$

Step 6.3

At $- 2.33606797$ , the second derivative is $- 0.00761154$ . Since this is negative, the second derivative is decreasing on the interval $(- \infty, - 2.23606797)$

Decreasing on $(- \infty, - 2.23606797)$ since $f'' (x) < 0$

Step 7

Substitute a value from the interval $(- 2.23606797, 2.23606797)$ into the second derivative to determine if it is increasing or decreasing.

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Step 7.1

Replace the variable $x$ with $0$ in the expression.

$f'' (0) = \frac{{(0)}^{2} \ln (9) + (0) \ln (243) \ln (9) - {(0)}^{2} \ln (81) + 0 \ln (3) \ln (59049) + \ln (59049)}{{({(0)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2

Simplify the result.

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Step 7.2.1

Simplify the numerator.

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Step 7.2.1.1

Raising $0$ to any positive power yields $0$ .

$f'' (0) = \frac{0 \ln (9) + 0 \ln (243) \ln (9) - 0^{2} \ln (81) + 0 \ln (3) \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.2

Multiply $0$ by $\ln (9)$ .

$f'' (0) = \frac{0 + 0 \ln (243) \ln (9) - 0^{2} \ln (81) + 0 \ln (3) \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.3

Multiply $0$ by $\ln (243)$ .

$f'' (0) = \frac{0 + 0 \ln (9) - 0^{2} \ln (81) + 0 \ln (3) \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.4

Multiply $0$ by $\ln (9)$ .

$f'' (0) = \frac{0 + 0 - 0^{2} \ln (81) + 0 \ln (3) \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.5

Raising $0$ to any positive power yields $0$ .

$f'' (0) = \frac{0 + 0 + 0 \ln (81) + 0 \ln (3) \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.6

Multiply $- 1$ by $0$ .

$f'' (0) = \frac{0 + 0 + 0 \ln (81) + 0 \ln (3) \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.7

Multiply $0$ by $\ln (81)$ .

$f'' (0) = \frac{0 + 0 + 0 + 0 \ln (3) \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.8

Multiply $0$ by $\ln (3)$ .

$f'' (0) = \frac{0 + 0 + 0 + 0 \ln (59049) + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.9

Multiply $0$ by $\ln (59049)$ .

$f'' (0) = \frac{0 + 0 + 0 + 0 + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.10

Add $0$ and $0$ .

$f'' (0) = \frac{0 + 0 + 0 + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.11

Add $0$ and $0$ .

$f'' (0) = \frac{0 + 0 + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.12

Add $0$ and $0$ .

$f'' (0) = \frac{0 + \ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.1.13

Add $0$ and $\ln (59049)$ .

$f'' (0) = \frac{\ln (59049)}{{(0^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.2

Simplify the denominator.

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Step 7.2.2.1

Raising $0$ to any positive power yields $0$ .

$f'' (0) = \frac{\ln (59049)}{{(0 \ln (3) + 5 \ln (3))}^{2}}$

Step 7.2.2.2

Multiply $0$ by $\ln (3)$ .

$f'' (0) = \frac{\ln (59049)}{{(0 + 5 \ln (3))}^{2}}$

Step 7.2.2.3

Simplify $5 \ln (3)$ by moving $5$ inside the logarithm.

$f'' (0) = \frac{\ln (59049)}{{(0 + \ln (3^{5}))}^{2}}$

Step 7.2.2.4

Raise $3$ to the power of $5$ .

$f'' (0) = \frac{\ln (59049)}{{(0 + \ln (243))}^{2}}$

Step 7.2.2.5

Add $0$ and $\ln (243)$ .

$f'' (0) = \frac{\ln (59049)}{\ln^{2} (243)}$

Step 7.2.3

The final answer is $\frac{\ln (59049)}{\ln^{2} (243)}$ .

$\frac{\ln (59049)}{\ln^{2} (243)}$

Step 7.3

At $0$ , the second derivative is $0.36409569$ . Since this is positive, the second derivative is increasing on the interval $(- 2.23606797, 2.23606797)$ .

Increasing on $(- 2.23606797, 2.23606797)$ since $f'' (x) > 0$

Step 8

Substitute a value from the interval $(2.23606797, \infty)$ into the second derivative to determine if it is increasing or decreasing.

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Step 8.1

Replace the variable $x$ with $2.33606797$ in the expression.

$f'' (2.33606797) = \frac{{(2.33606797)}^{2} \ln (9) + (2.33606797) \ln (243) \ln (9) - {(2.33606797)}^{2} \ln (81) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({(2.33606797)}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2

Simplify the result.

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Step 8.2.1

Simplify the numerator.

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Step 8.2.1.1

Raise $2.33606797$ to the power of $2$ .

$f'' (2.33606797) = \frac{5.45721359 \ln (9) + 2.33606797 \ln (243) \ln (9) - {2.33606797}^{2} \ln (81) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.2

Simplify $5.45721359 \ln (9)$ by moving $5.45721359$ inside the logarithm.

$f'' (2.33606797) = \frac{\ln (9^{5.45721359}) + 2.33606797 \ln (243) \ln (9) - {2.33606797}^{2} \ln (81) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.3

Raise $9$ to the power of $5.45721359$ .

$f'' (2.33606797) = \frac{\ln (161252.03194789) + 2.33606797 \ln (243) \ln (9) - {2.33606797}^{2} \ln (81) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.4

Simplify $2.33606797 \ln (243)$ by moving $2.33606797$ inside the logarithm.

$f'' (2.33606797) = \frac{\ln (161252.03194789) + \ln (243^{2.33606797}) \ln (9) - {2.33606797}^{2} \ln (81) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.5

Raise $243$ to the power of $2.33606797$ .

$f'' (2.33606797) = \frac{\ln (161252.03194789) + \ln (374057.54800345) \ln (9) - {2.33606797}^{2} \ln (81) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.6

Raise $2.33606797$ to the power of $2$ .

$f'' (2.33606797) = \frac{\ln (161252.03194789) + \ln (374057.54800345) \ln (9) - 1 \cdot (5.45721359 \ln (81)) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.7

Multiply $- 1$ by $5.45721359$ .

$f'' (2.33606797) = \frac{\ln (161252.03194789) + \ln (374057.54800345) \ln (9) - 5.45721359 \ln (81) - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.8

Multiply $- 5.45721359$ by $\ln (81)$ .

$f'' (2.33606797) = \frac{\ln (161252.03194789) + \ln (374057.54800345) \ln (9) - 23.98144767 - 2.33606797 \ln (3) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.9

Simplify $- 2.33606797 \ln (3)$ by moving $2.33606797$ inside the logarithm.

$f'' (2.33606797) = \frac{\ln (161252.03194789) + \ln (374057.54800345) \ln (9) - 23.98144767 - \ln (3^{2.33606797}) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.10

Raise $3$ to the power of $2.33606797$ .

$f'' (2.33606797) = \frac{\ln (161252.03194789) + \ln (374057.54800345) \ln (9) - 23.98144767 - \ln (13.0193015) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.11

Subtract $23.98144767$ from $\ln (161252.03194789)$ .

$f'' (2.33606797) = \frac{\ln (374057.54800345) \ln (9) - 11.99072383 - \ln (13.0193015) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.12

Subtract $11.99072383$ from $\ln (374057.54800345) \ln (9)$ .

$f'' (2.33606797) = \frac{16.20442434 - \ln (13.0193015) \ln (59049) + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.13

Subtract $\ln (13.0193015) \ln (59049)$ from $16.20442434$ .

$f'' (2.33606797) = \frac{- 11.99072383 + \ln (59049)}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.1.14

Add $- 11.99072383$ and $\ln (59049)$ .

$f'' (2.33606797) = \frac{- 1.00460094}{{({2.33606797}^{2} \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.2

Simplify the denominator.

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Step 8.2.2.1

Raise $2.33606797$ to the power of $2$ .

$f'' (2.33606797) = \frac{- 1.00460094}{{(5.45721359 \ln (3) + 5 \ln (3))}^{2}}$

Step 8.2.2.2

Simplify $5.45721359 \ln (3)$ by moving $5.45721359$ inside the logarithm.

$f'' (2.33606797) = \frac{- 1.00460094}{{(\ln (3^{5.45721359}) + 5 \ln (3))}^{2}}$

Step 8.2.2.3

Raise $3$ to the power of $5.45721359$ .

$f'' (2.33606797) = \frac{- 1.00460094}{{(\ln (401.56199016) + 5 \ln (3))}^{2}}$

Step 8.2.2.4

Simplify $5 \ln (3)$ by moving $5$ inside the logarithm.

$f'' (2.33606797) = \frac{- 1.00460094}{{(\ln (401.56199016) + \ln (3^{5}))}^{2}}$

Step 8.2.2.5

Raise $3$ to the power of $5$ .

$f'' (2.33606797) = \frac{- 1.00460094}{{(\ln (401.56199016) + \ln (243))}^{2}}$

Step 8.2.2.6

Use the product property of logarithms, $\log_{b} (x) + \log_{b} (y) = \log_{b} (x y)$ .

$f'' (2.33606797) = \frac{- 1.00460094}{\ln^{2} (401.56199016 \cdot 243)}$

Step 8.2.2.7

Multiply $401.56199016$ by $243$ .

$f'' (2.33606797) = \frac{- 1.00460094}{\ln^{2} (97579.56361088)}$

Step 8.2.3

Move the negative in front of the fraction.

$f'' (2.33606797) = - \frac{1.00460094}{\ln^{2} (97579.56361088)}$

Step 8.2.4

Replace $e$ with an approximation.

$f'' (2.33606797) = - \frac{1.00460094}{{\log_{2.71828182}}^{2} (97579.56361088)}$

Step 8.2.5

Log base $2.71828182$ of $97579.56361088$ is approximately $11.48842336$ .

$f'' (2.33606797) = - \frac{1.00460094}{{11.48842336}^{2}}$

Step 8.2.6

Raise $11.48842336$ to the power of $2$ .

$f'' (2.33606797) = - \frac{1.00460094}{131.98387132}$

Step 8.2.7

Divide $1.00460094$ by $131.98387132$ .

$f'' (2.33606797) = - 1 \cdot 0.00761154$

Step 8.2.8

Multiply $- 1$ by $0.00761154$ .

$f'' (2.33606797) = - 0.00761154$

Step 8.2.9

The final answer is $- 0.00761154$ .

$- 0.00761154$

Step 8.3

At $2.33606797$ , the second derivative is $- 0.00761154$ . Since this is negative, the second derivative is decreasing on the interval $(2.23606797, \infty)$

Decreasing on $(2.23606797, \infty)$ since $f'' (x) < 0$

Step 9

An inflection point is a point on a curve at which the concavity changes sign from plus to minus or from minus to plus. The inflection points in this case are $(- 2.23606797, - 0.1401647), (2.23606797, 4.33197125)$ .

$(- 2.23606797, - 0.1401647), (2.23606797, 4.33197125)$

Step 10