Calculus Examples

$f (x) = (2 x - 1) (x + 4)$ , $(1, 5)$

Step 1

The domain of the expression is all real numbers except where the expression is undefined. In this case, there is no real number that makes the expression undefined.

Interval Notation:

$(- \infty, \infty)$

Set-Builder Notation:

${x | x \in ℝ}$

Step 2

$f (x)$ is continuous on $[1, 5]$ .

$f (x)$ is continuous

Step 3

The average value of function $f$ over the interval $[a, b]$ is defined as $A (x) = \frac{1}{b - a} \int_{a}^{b} f (x) d x$ .

$A (x) = \frac{1}{b - a} \int_{a}^{b} f (x) d x$

Step 4

Substitute the actual values into the formula for the average value of a function.

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} (2 x - 1) (x + 4) d x)$

Step 5

Simplify.

Tap for more steps...

Step 5.1

Apply the distributive property.

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x (x + 4) - 1 (x + 4) d x)$

Step 5.2

Apply the distributive property.

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x \cdot x + 2 x \cdot 4 - 1 (x + 4) d x)$

Step 5.3

Apply the distributive property.

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x \cdot x + 2 x \cdot 4 - 1 x - 1 \cdot 4 d x)$

Step 5.4

Move $x$ .

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x \cdot x + 2 \cdot (4 x) - 1 x - 1 \cdot 4 d x)$

Step 5.5

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

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 (x \cdot x) + 2 \cdot (4 x) - 1 x - 1 \cdot 4 d x)$

Step 5.6

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

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 (x \cdot x) + 2 \cdot (4 x) - 1 x - 1 \cdot 4 d x)$

Step 5.7

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

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x^{1 + 1} + 2 \cdot (4 x) - 1 x - 1 \cdot 4 d x)$

Step 5.8

Add $1$ and $1$ .

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x^{2} + 2 \cdot (4 x) - 1 x - 1 \cdot 4 d x)$

Step 5.9

Multiply $2$ by $4$ .

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x^{2} + 8 x - 1 x - 1 \cdot 4 d x)$

Step 5.10

Multiply $- 1$ by $4$ .

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x^{2} + 8 x - 1 x - 4 d x)$

Step 5.11

Subtract $1 x$ from $8 x$ .

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x^{2} + 7 x - 4 d x)$

Step 6

Split the single integral into multiple integrals.

$A (x) = \frac{1}{5 - 1} (\int_{1}^{5} 2 x^{2} d x + \int_{1}^{5} 7 x d x + \int_{1}^{5} - 4 d x)$

Step 7

Since $2$ is constant with respect to $x$ , move $2$ out of the integral.

$A (x) = \frac{1}{5 - 1} (2 \int_{1}^{5} x^{2} d x + \int_{1}^{5} 7 x d x + \int_{1}^{5} - 4 d x)$

Step 8

By the Power Rule, the integral of $x^{2}$ with respect to $x$ is $\frac{1}{3} x^{3}$ .

$A (x) = \frac{1}{5 - 1} (2 (\frac{1}{3} x^{3}]_{1}^{5}) + \int_{1}^{5} 7 x d x + \int_{1}^{5} - 4 d x)$

Step 9

Combine $\frac{1}{3}$ and $x^{3}$ .

$A (x) = \frac{1}{5 - 1} (2 (\frac{x^{3}}{3}]_{1}^{5}) + \int_{1}^{5} 7 x d x + \int_{1}^{5} - 4 d x)$

Step 10

Since $7$ is constant with respect to $x$ , move $7$ out of the integral.

$A (x) = \frac{1}{5 - 1} (2 (\frac{x^{3}}{3}]_{1}^{5}) + 7 \int_{1}^{5} x d x + \int_{1}^{5} - 4 d x)$

Step 11

By the Power Rule, the integral of $x$ with respect to $x$ is $\frac{1}{2} x^{2}$ .

$A (x) = \frac{1}{5 - 1} (2 (\frac{x^{3}}{3}]_{1}^{5}) + 7 (\frac{1}{2} x^{2}]_{1}^{5}) + \int_{1}^{5} - 4 d x)$

Step 12

Combine $\frac{1}{2}$ and $x^{2}$ .

$A (x) = \frac{1}{5 - 1} (2 (\frac{x^{3}}{3}]_{1}^{5}) + 7 (\frac{x^{2}}{2}]_{1}^{5}) + \int_{1}^{5} - 4 d x)$

Step 13

Apply the constant rule.

$A (x) = \frac{1}{5 - 1} (2 (\frac{x^{3}}{3}]_{1}^{5}) + 7 (\frac{x^{2}}{2}]_{1}^{5}) + - 4 x]_{1}^{5})$

Step 14

Substitute and simplify.

Tap for more steps...

Step 14.1

Evaluate $\frac{x^{3}}{3}$ at $5$ and at $1$ .

$A (x) = \frac{1}{5 - 1} (2 ((\frac{5^{3}}{3}) - \frac{1^{3}}{3}) + 7 (\frac{x^{2}}{2}]_{1}^{5}) + - 4 x]_{1}^{5})$

Step 14.2

Evaluate $\frac{x^{2}}{2}$ at $5$ and at $1$ .

$A (x) = \frac{1}{5 - 1} (2 (\frac{5^{3}}{3} - \frac{1^{3}}{3}) + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) + - 4 x]_{1}^{5})$

Step 14.3

Evaluate $- 4 x$ at $5$ and at $1$ .

$A (x) = \frac{1}{5 - 1} (2 (\frac{5^{3}}{3} - \frac{1^{3}}{3}) + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4

Simplify.

Tap for more steps...

Step 14.4.1

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

$A (x) = \frac{1}{5 - 1} (2 (\frac{125}{3} - \frac{1^{3}}{3}) + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.2

One to any power is one.

$A (x) = \frac{1}{5 - 1} (2 (\frac{125}{3} - \frac{1}{3}) + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.3

Combine the numerators over the common denominator.

$A (x) = \frac{1}{5 - 1} (2 (\frac{125 - 1}{3}) + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.4

Subtract $1$ from $125$ .

$A (x) = \frac{1}{5 - 1} (2 (\frac{124}{3}) + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.5

Combine $2$ and $\frac{124}{3}$ .

$A (x) = \frac{1}{5 - 1} (\frac{2 \cdot 124}{3} + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.6

Multiply $2$ by $124$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{5^{2}}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.7

Raise $5$ to the power of $2$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{25}{2} - \frac{1^{2}}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.8

One to any power is one.

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{25}{2} - \frac{1}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.9

Combine the numerators over the common denominator.

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{25 - 1}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.10

Subtract $1$ from $25$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{24}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.11

Cancel the common factor of $24$ and $2$ .

Tap for more steps...

Step 14.4.11.1

Factor $2$ out of $24$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{2 \cdot 12}{2}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.11.2

Cancel the common factors.

Tap for more steps...

Step 14.4.11.2.1

Factor $2$ out of $2$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{2 \cdot 12}{2 (1)}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.11.2.2

Cancel the common factor.

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{2 \cdot 12}{2 \cdot 1}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.11.2.3

Rewrite the expression.

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 (\frac{12}{1}) - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.11.2.4

Divide $12$ by $1$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 7 \cdot 12 - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.12

Multiply $7$ by $12$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 84 - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.13

To write $84$ as a fraction with a common denominator, multiply by $\frac{3}{3}$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + 84 \cdot \frac{3}{3} - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.14

Combine $84$ and $\frac{3}{3}$ .

$A (x) = \frac{1}{5 - 1} (\frac{248}{3} + \frac{84 \cdot 3}{3} - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.15

Combine the numerators over the common denominator.

$A (x) = \frac{1}{5 - 1} (\frac{248 + 84 \cdot 3}{3} - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.16

Simplify the numerator.

Tap for more steps...

Step 14.4.16.1

Multiply $84$ by $3$ .

$A (x) = \frac{1}{5 - 1} (\frac{248 + 252}{3} - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.16.2

Add $248$ and $252$ .

$A (x) = \frac{1}{5 - 1} (\frac{500}{3} - 4 \cdot 5 + 4 \cdot 1)$

Step 14.4.17

Multiply $- 4$ by $5$ .

$A (x) = \frac{1}{5 - 1} (\frac{500}{3} - 20 + 4 \cdot 1)$

Step 14.4.18

Multiply $4$ by $1$ .

$A (x) = \frac{1}{5 - 1} (\frac{500}{3} - 20 + 4)$

Step 14.4.19

Add $- 20$ and $4$ .

$A (x) = \frac{1}{5 - 1} (\frac{500}{3} - 16)$

Step 14.4.20

To write $- 16$ as a fraction with a common denominator, multiply by $\frac{3}{3}$ .

$A (x) = \frac{1}{5 - 1} (\frac{500}{3} - 16 \cdot \frac{3}{3})$

Step 14.4.21

Combine $- 16$ and $\frac{3}{3}$ .

$A (x) = \frac{1}{5 - 1} (\frac{500}{3} + \frac{- 16 \cdot 3}{3})$

Step 14.4.22

Combine the numerators over the common denominator.

$A (x) = \frac{1}{5 - 1} (\frac{500 - 16 \cdot 3}{3})$

Step 14.4.23

Simplify the numerator.

Tap for more steps...

Step 14.4.23.1

Multiply $- 16$ by $3$ .

$A (x) = \frac{1}{5 - 1} (\frac{500 - 48}{3})$

Step 14.4.23.2

Subtract $48$ from $500$ .

$A (x) = \frac{1}{5 - 1} (\frac{452}{3})$

Step 15

Subtract $1$ from $5$ .

$A (x) = \frac{1}{4} \cdot \frac{452}{3}$

Step 16

Cancel the common factor of $4$ .

Tap for more steps...

Step 16.1

Factor $4$ out of $452$ .

$A (x) = \frac{1}{4} \cdot \frac{4 (113)}{3}$

Step 16.2

Cancel the common factor.

$A (x) = \frac{1}{4} \cdot \frac{4 \cdot 113}{3}$

Step 16.3

Rewrite the expression.

$A (x) = \frac{113}{3}$

Step 17