Calculus Examples

$\frac{\sin^{2} (x)}{1 + \cos (x)}$

Step 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 $f (x) = \sin^{2} (x)$ and $g (x) = 1 + \cos (x)$ .

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

Step 2

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

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Step 2.1

To apply the Chain Rule, set $u$ as $\sin (x)$ .

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

Step 2.2

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

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

Step 2.3

Replace all occurrences of $u$ with $\sin (x)$ .

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

Step 3

Move $2$ to the left of $1 + \cos (x)$ .

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

Step 4

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

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

Step 5

Differentiate.

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Step 5.1

By the Sum Rule, the derivative of $1 + \cos (x)$ with respect to $x$ is $\frac{d}{d x} [1] + \frac{d}{d x} [\cos (x)]$ .

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

Step 5.2

Since $1$ is constant with respect to $x$ , the derivative of $1$ with respect to $x$ is $0$ .

$\frac{2 (1 + \cos (x)) \sin (x) \cos (x) - \sin^{2} (x) (0 + \frac{d}{d x} [\cos (x)])}{{(1 + \cos (x))}^{2}}$

Step 5.3

Add $0$ and $\frac{d}{d x} [\cos (x)]$ .

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

Step 6

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

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

Step 7

Multiply.

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Step 7.1

Multiply $- 1$ by $- 1$ .

$\frac{2 (1 + \cos (x)) \sin (x) \cos (x) + 1 \sin^{2} (x) \sin (x)}{{(1 + \cos (x))}^{2}}$

Step 7.2

Multiply $\sin^{2} (x)$ by $1$ .

$\frac{2 (1 + \cos (x)) \sin (x) \cos (x) + \sin^{2} (x) \sin (x)}{{(1 + \cos (x))}^{2}}$

Step 8

Multiply $\sin^{2} (x)$ by $\sin (x)$ by adding the exponents.

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Step 8.1

Multiply $\sin^{2} (x)$ by $\sin (x)$ .

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Step 8.1.1

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

$\frac{2 (1 + \cos (x)) \sin (x) \cos (x) + \sin^{2} (x) \sin^{1} (x)}{{(1 + \cos (x))}^{2}}$

Step 8.1.2

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

$\frac{2 (1 + \cos (x)) \sin (x) \cos (x) + {\sin (x)}^{2 + 1}}{{(1 + \cos (x))}^{2}}$

Step 8.2

Add $2$ and $1$ .

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

Step 9

Simplify.

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Step 9.1

Apply the distributive property.

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

Step 9.2

Apply the distributive property.

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

Step 9.3

Apply the distributive property.

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

Step 9.4

Simplify each term.

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Step 9.4.1

Multiply $2$ by $1$ .

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

Step 9.4.2

Apply the sine double-angle identity.

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

Step 9.4.3

Reorder $2 \cos (x)$ and $\sin (x)$ .

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

Step 9.4.4

Reorder $\sin (x)$ and $2$ .

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

Step 9.4.5

Apply the sine double-angle identity.

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

Step 9.5

Reorder terms.

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