Calculus Examples

$f (x) = - 4 \sin (x) \cos^{3} (x) - 4 \sin^{3} (x) \cos (x)$

Step 1

By the Sum Rule, the derivative of $- 4 \sin (x) \cos^{3} (x) - 4 \sin^{3} (x) \cos (x)$ with respect to $x$ is $\frac{d}{d x} [- 4 \sin (x) \cos^{3} (x)] + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$ .

$\frac{d}{d x} [- 4 \sin (x) \cos^{3} (x)] + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2

Evaluate $\frac{d}{d x} [- 4 \sin (x) \cos^{3} (x)]$ .

Tap for more steps...

Step 2.1

Since $- 4$ is constant with respect to $x$ , the derivative of $- 4 \sin (x) \cos^{3} (x)$ with respect to $x$ is $- 4 \frac{d}{d x} [\sin (x) \cos^{3} (x)]$ .

$- 4 \frac{d}{d x} [\sin (x) \cos^{3} (x)] + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.2

Differentiate using the Product Rule which states that $\frac{d}{d x} [f (x) g (x)]$ is $f (x) \frac{d}{d x} [g (x)] + g (x) \frac{d}{d x} [f (x)]$ where $f (x) = \sin (x)$ and $g (x) = \cos^{3} (x)$ .

$- 4 (\sin (x) \frac{d}{d x} [\cos^{3} (x)] + \cos^{3} (x) \frac{d}{d x} [\sin (x)]) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.3

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

Tap for more steps...

Step 2.3.1

To apply the Chain Rule, set $u_{1}$ as $\cos (x)$ .

$- 4 (\sin (x) (\frac{d}{d u_{1}} [{u_{1}}^{3}] \frac{d}{d x} [\cos (x)]) + \cos^{3} (x) \frac{d}{d x} [\sin (x)]) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.3.2

Differentiate using the Power Rule which states that $\frac{d}{d u_{1}} [{u_{1}}^{n}]$ is $n {u_{1}}^{n - 1}$ where $n = 3$ .

$- 4 (\sin (x) (3 {u_{1}}^{2} \frac{d}{d x} [\cos (x)]) + \cos^{3} (x) \frac{d}{d x} [\sin (x)]) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.3.3

Replace all occurrences of $u_{1}$ with $\cos (x)$ .

$- 4 (\sin (x) (3 \cos^{2} (x) \frac{d}{d x} [\cos (x)]) + \cos^{3} (x) \frac{d}{d x} [\sin (x)]) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.4

The derivative of $\cos (x)$ with respect to $x$ is $- \sin (x)$ .

$- 4 (\sin (x) (3 \cos^{2} (x) (- \sin (x))) + \cos^{3} (x) \frac{d}{d x} [\sin (x)]) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.5

The derivative of $\sin (x)$ with respect to $x$ is $\cos (x)$ .

$- 4 (\sin (x) (3 \cos^{2} (x) (- \sin (x))) + \cos^{3} (x) \cos (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.6

Multiply $- 1$ by $3$ .

$- 4 (\sin (x) (- 3 \cos^{2} (x) \sin (x)) + \cos^{3} (x) \cos (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.7

Raise $\sin (x)$ to the power of $1$ .

$- 4 (- 3 \cos^{2} (x) (\sin^{1} (x) \sin (x)) + \cos^{3} (x) \cos (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.8

Raise $\sin (x)$ to the power of $1$ .

$- 4 (- 3 \cos^{2} (x) (\sin^{1} (x) \sin^{1} (x)) + \cos^{3} (x) \cos (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.9

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

$- 4 (- 3 \cos^{2} (x) {\sin (x)}^{1 + 1} + \cos^{3} (x) \cos (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.10

Add $1$ and $1$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{3} (x) \cos (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.11

Multiply $\cos^{3} (x)$ by $\cos (x)$ by adding the exponents.

Tap for more steps...

Step 2.11.1

Multiply $\cos^{3} (x)$ by $\cos (x)$ .

Tap for more steps...

Step 2.11.1.1

Raise $\cos (x)$ to the power of $1$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{3} (x) \cos^{1} (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.11.1.2

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

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + {\cos (x)}^{3 + 1}) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 2.11.2

Add $3$ and $1$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) + \frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$

Step 3

Evaluate $\frac{d}{d x} [- 4 \sin^{3} (x) \cos (x)]$ .

Tap for more steps...

Step 3.1

Since $- 4$ is constant with respect to $x$ , the derivative of $- 4 \sin^{3} (x) \cos (x)$ with respect to $x$ is $- 4 \frac{d}{d x} [\sin^{3} (x) \cos (x)]$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 \frac{d}{d x} [\sin^{3} (x) \cos (x)]$

Step 3.2

Differentiate using the Product Rule which states that $\frac{d}{d x} [f (x) g (x)]$ is $f (x) \frac{d}{d x} [g (x)] + g (x) \frac{d}{d x} [f (x)]$ where $f (x) = \sin^{3} (x)$ and $g (x) = \cos (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{3} (x) \frac{d}{d x} [\cos (x)] + \cos (x) \frac{d}{d x} [\sin^{3} (x)])$

Step 3.3

The derivative of $\cos (x)$ with respect to $x$ is $- \sin (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{3} (x) (- \sin (x)) + \cos (x) \frac{d}{d x} [\sin^{3} (x)])$

Step 3.4

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

Tap for more steps...

Step 3.4.1

To apply the Chain Rule, set $u_{2}$ as $\sin (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{3} (x) (- \sin (x)) + \cos (x) (\frac{d}{d u_{2}} [{u_{2}}^{3}] \frac{d}{d x} [\sin (x)]))$

Step 3.4.2

Differentiate using the Power Rule which states that $\frac{d}{d u_{2}} [{u_{2}}^{n}]$ is $n {u_{2}}^{n - 1}$ where $n = 3$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{3} (x) (- \sin (x)) + \cos (x) (3 {u_{2}}^{2} \frac{d}{d x} [\sin (x)]))$

Step 3.4.3

Replace all occurrences of $u_{2}$ with $\sin (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{3} (x) (- \sin (x)) + \cos (x) (3 \sin^{2} (x) \frac{d}{d x} [\sin (x)]))$

Step 3.5

The derivative of $\sin (x)$ with respect to $x$ is $\cos (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{3} (x) (- \sin (x)) + \cos (x) (3 \sin^{2} (x) \cos (x)))$

Step 3.6

Multiply $\sin^{3} (x)$ by $\sin (x)$ by adding the exponents.

Tap for more steps...

Step 3.6.1

Move $\sin (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin (x) \sin^{3} (x) \cdot - 1 + \cos (x) (3 \sin^{2} (x) \cos (x)))$

Step 3.6.2

Multiply $\sin (x)$ by $\sin^{3} (x)$ .

Tap for more steps...

Step 3.6.2.1

Raise $\sin (x)$ to the power of $1$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{1} (x) \sin^{3} (x) \cdot - 1 + \cos (x) (3 \sin^{2} (x) \cos (x)))$

Step 3.6.2.2

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

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 ({\sin (x)}^{1 + 3} \cdot - 1 + \cos (x) (3 \sin^{2} (x) \cos (x)))$

Step 3.6.3

Add $1$ and $3$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (\sin^{4} (x) \cdot - 1 + \cos (x) (3 \sin^{2} (x) \cos (x)))$

Step 3.7

Move $- 1$ to the left of $\sin^{4} (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (- 1 \cdot \sin^{4} (x) + \cos (x) (3 \sin^{2} (x) \cos (x)))$

Step 3.8

Rewrite $- 1 \sin^{4} (x)$ as $- \sin^{4} (x)$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (- \sin^{4} (x) + \cos (x) (3 \sin^{2} (x) \cos (x)))$

Step 3.9

Raise $\cos (x)$ to the power of $1$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (- \sin^{4} (x) + 3 \sin^{2} (x) (\cos^{1} (x) \cos (x)))$

Step 3.10

Raise $\cos (x)$ to the power of $1$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (- \sin^{4} (x) + 3 \sin^{2} (x) (\cos^{1} (x) \cos^{1} (x)))$

Step 3.11

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

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (- \sin^{4} (x) + 3 \sin^{2} (x) {\cos (x)}^{1 + 1})$

Step 3.12

Add $1$ and $1$ .

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x) + \cos^{4} (x)) - 4 (- \sin^{4} (x) + 3 \sin^{2} (x) \cos^{2} (x))$

Step 4

Simplify.

Tap for more steps...

Step 4.1

Apply the distributive property.

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x)) - 4 \cos^{4} (x) - 4 (- \sin^{4} (x) + 3 \sin^{2} (x) \cos^{2} (x))$

Step 4.2

Apply the distributive property.

$- 4 (- 3 \cos^{2} (x) \sin^{2} (x)) - 4 \cos^{4} (x) - 4 (- \sin^{4} (x)) - 4 (3 \sin^{2} (x) \cos^{2} (x))$

Step 4.3

Combine terms.

Tap for more steps...

Step 4.3.1

Multiply $- 3$ by $- 4$ .

$12 (\cos^{2} (x) \sin^{2} (x)) - 4 \cos^{4} (x) - 4 (- \sin^{4} (x)) - 4 (3 \sin^{2} (x) \cos^{2} (x))$

Step 4.3.2

Multiply $- 1$ by $- 4$ .

$12 \cos^{2} (x) \sin^{2} (x) - 4 \cos^{4} (x) + 4 \sin^{4} (x) - 4 (3 \sin^{2} (x) \cos^{2} (x))$

Step 4.3.3

Multiply $3$ by $- 4$ .

$12 \cos^{2} (x) \sin^{2} (x) - 4 \cos^{4} (x) + 4 \sin^{4} (x) - 12 (\sin^{2} (x) \cos^{2} (x))$

Step 4.3.4

Reorder the factors of $- 12 \sin^{2} (x) \cos^{2} (x)$ .

$12 \cos^{2} (x) \sin^{2} (x) - 4 \cos^{4} (x) + 4 \sin^{4} (x) - 12 \cos^{2} (x) \sin^{2} (x)$

Step 4.3.5

Subtract $12 \cos^{2} (x) \sin^{2} (x)$ from $12 \cos^{2} (x) \sin^{2} (x)$ .

$0 - 4 \cos^{4} (x) + 4 \sin^{4} (x)$

Step 4.3.6

Subtract $4 \cos^{4} (x)$ from $0$ .

$- 4 \cos^{4} (x) + 4 \sin^{4} (x)$

Step 4.4

Rewrite $4 \sin^{4} (x)$ as ${(2 \sin^{2} (x))}^{2}$ .

$- 4 \cos^{4} (x) + {(2 \sin^{2} (x))}^{2}$

Step 4.5

Rewrite $4 \cos^{4} (x)$ as ${(2 \cos^{2} (x))}^{2}$ .

$- {(2 \cos^{2} (x))}^{2} + {(2 \sin^{2} (x))}^{2}$

Step 4.6

Reorder $- {(2 \cos^{2} (x))}^{2}$ and ${(2 \sin^{2} (x))}^{2}$ .

${(2 \sin^{2} (x))}^{2} - {(2 \cos^{2} (x))}^{2}$

Step 4.7

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = 2 \sin^{2} (x)$ and $b = 2 \cos^{2} (x)$ .

$(2 \sin^{2} (x) + 2 \cos^{2} (x)) (2 \sin^{2} (x) - (2 \cos^{2} (x)))$

Step 4.8

Factor $2$ out of $2 \sin^{2} (x)$ .

$(2 (\sin^{2} (x)) + 2 \cos^{2} (x)) (2 \sin^{2} (x) - (2 \cos^{2} (x)))$

Step 4.9

Factor $2$ out of $2 \cos^{2} (x)$ .

$(2 (\sin^{2} (x)) + 2 (\cos^{2} (x))) (2 \sin^{2} (x) - (2 \cos^{2} (x)))$

Step 4.10

Factor $2$ out of $2 (\sin^{2} (x)) + 2 (\cos^{2} (x))$ .

$2 (\sin^{2} (x) + \cos^{2} (x)) (2 \sin^{2} (x) - (2 \cos^{2} (x)))$

Step 4.11

Apply pythagorean identity.

$2 \cdot 1 (2 \sin^{2} (x) - (2 \cos^{2} (x)))$

Step 4.12

Multiply $2$ by $1$ .

$2 (2 \sin^{2} (x) - (2 \cos^{2} (x)))$

Step 4.13

Multiply $2$ by $- 1$ .

$2 (2 \sin^{2} (x) - 2 \cos^{2} (x))$

Step 4.14

Apply the distributive property.

$2 (2 \sin^{2} (x)) + 2 (- 2 \cos^{2} (x))$

Step 4.15

Multiply $2$ by $2$ .

$4 \sin^{2} (x) + 2 (- 2 \cos^{2} (x))$

Step 4.16

Multiply $- 2$ by $2$ .

$4 \sin^{2} (x) - 4 \cos^{2} (x)$