Precalculus Examples

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

Step 1

Simplify the numerator.

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Step 1.1

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

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

Step 1.2

Combine $x^{2}$ and $\frac{1}{{(4 - x^{2})}^{\frac{1}{2}}}$ .

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

Step 1.3

To write ${(4 - x^{2})}^{\frac{1}{2}}$ as a fraction with a common denominator, multiply by $\frac{{(4 - x^{2})}^{\frac{1}{2}}}{{(4 - x^{2})}^{\frac{1}{2}}}$ .

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

Step 1.4

Combine the numerators over the common denominator.

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

Step 1.5

Reorder terms.

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

Step 1.6

Rewrite $\frac{x^{2} + {(4 - x^{2})}^{\frac{1}{2}} {(4 - x^{2})}^{\frac{1}{2}}}{{(- x^{2} + 4)}^{\frac{1}{2}}}$ in a factored form.

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Step 1.6.1

Multiply ${(4 - x^{2})}^{\frac{1}{2}}$ by ${(4 - x^{2})}^{\frac{1}{2}}$ by adding the exponents.

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Step 1.6.1.1

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

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

Step 1.6.1.2

Combine the numerators over the common denominator.

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

Step 1.6.1.3

Add $1$ and $1$ .

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

Step 1.6.1.4

Divide $2$ by $2$ .

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

Step 1.6.2

Simplify ${(4 - x^{2})}^{1}$ .

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

Step 1.6.3

Subtract $x^{2}$ from $x^{2}$ .

$\frac{\frac{0 + 4}{{(- x^{2} + 4)}^{\frac{1}{2}}}}{4 - x^{2}}$

Step 1.6.4

Add $0$ and $4$ .

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

Step 2

Simplify the denominator.

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Step 2.1

Rewrite $4$ as $2^{2}$ .

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

Step 2.2

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

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

Step 3

Multiply the numerator by the reciprocal of the denominator.

$\frac{4}{{(- x^{2} + 4)}^{\frac{1}{2}}} \cdot \frac{1}{(2 + x) (2 - x)}$

Step 4

Combine.

$\frac{4 \cdot 1}{{(- x^{2} + 4)}^{\frac{1}{2}} ((2 + x) (2 - x))}$

Step 5

Multiply $4$ by $1$ .

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