Calculus Examples

$\int \frac{- 4 x}{{(1 - 2 x^{2})}^{2}} d x$

Step 1

Move the negative in front of the fraction.

$\int - \frac{4 x}{{(1 - 2 x^{2})}^{2}} d x$

Step 2

Let $u = 1 - 2 x^{2}$ . Then $d u = - 4 x d x$ , so $\frac{1}{- 4 x} d u = d x$ . Rewrite using $u$ and $d$ $u$ .

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Step 2.1

Let $u = 1 - 2 x^{2}$ . Find $\frac{d u}{d x}$ .

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Step 2.1.1

Differentiate $1 - 2 x^{2}$ .

$\frac{d}{d x} [1 - 2 x^{2}]$

Step 2.1.2

Differentiate.

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Step 2.1.2.1

By the Sum Rule, the derivative of $1 - 2 x^{2}$ with respect to $x$ is $\frac{d}{d x} [1] + \frac{d}{d x} [- 2 x^{2}]$ .

$\frac{d}{d x} [1] + \frac{d}{d x} [- 2 x^{2}]$

Step 2.1.2.2

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

$0 + \frac{d}{d x} [- 2 x^{2}]$

Step 2.1.3

Evaluate $\frac{d}{d x} [- 2 x^{2}]$ .

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Step 2.1.3.1

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

$0 - 2 \frac{d}{d x} [x^{2}]$

Step 2.1.3.2

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

$0 - 2 (2 x)$

Step 2.1.3.3

Multiply $2$ by $- 2$ .

$0 - 4 x$

Step 2.1.4

Subtract $4 x$ from $0$ .

$- 4 x$

Step 2.2

Rewrite the problem using $u$ and $d u$ .

$\int - \frac{- 1}{u^{2}} d u$

Step 3

Simplify the expression.

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Step 3.1

Simplify.

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Step 3.1.1

Move the negative in front of the fraction.

$\int - - \frac{1}{u^{2}} d u$

Step 3.1.2

Multiply $- 1$ by $- 1$ .

$\int 1 \frac{1}{u^{2}} d u$

Step 3.1.3

Multiply $\frac{1}{u^{2}}$ by $1$ .

$\int \frac{1}{u^{2}} d u$

Step 3.2

Apply basic rules of exponents.

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Step 3.2.1

Move $u^{2}$ out of the denominator by raising it to the $- 1$ power.

$\int {(u^{2})}^{- 1} d u$

Step 3.2.2

Multiply the exponents in ${(u^{2})}^{- 1}$ .

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Step 3.2.2.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$\int u^{2 \cdot - 1} d u$

Step 3.2.2.2

Multiply $2$ by $- 1$ .

$\int u^{- 2} d u$

Step 4

By the Power Rule, the integral of $u^{- 2}$ with respect to $u$ is $- u^{- 1}$ .

$- u^{- 1} + C$

Step 5

Rewrite $- u^{- 1} + C$ as $- \frac{1}{u} + C$ .

$- \frac{1}{u} + C$

Step 6

Replace all occurrences of $u$ with $1 - 2 x^{2}$ .

$- \frac{1}{1 - 2 x^{2}} + C$