Calculus Examples

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

Step 1

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

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

Step 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 $f (x) = x^{3} \cos (x)$ and $g (x) = \sin (x)$ .

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

Step 3

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

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

Step 4

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

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

Step 5

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

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

Step 6

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

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

Step 7

Add $1$ and $1$ .

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

Step 8

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 $f (x) = x^{3}$ and $g (x) = \cos (x)$ .

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

Step 9

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

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

Step 10

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

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

Step 11

Simplify.

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Step 11.1

Apply the distributive property.

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

Step 11.2

Apply the distributive property.

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

Step 11.3

Combine terms.

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Step 11.3.1

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

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

Step 11.3.2

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

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

Step 11.3.3

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

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

Step 11.3.4

Add $1$ and $1$ .

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

Step 11.3.5

Multiply $- 1$ by $4$ .

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

Step 11.3.6

Multiply $3$ by $4$ .

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

Step 11.4

Reorder terms.

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