Trigonometry Examples

$\frac{1 - \sqrt{x}}{1 + \sqrt{x}} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 1

Multiply $\frac{1 - \sqrt{x}}{1 + \sqrt{x}}$ by $\frac{1 - \sqrt{x}}{1 - \sqrt{x}}$ .

$\frac{1 - \sqrt{x}}{1 + \sqrt{x}} \cdot \frac{1 - \sqrt{x}}{1 - \sqrt{x}} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 2

Multiply $\frac{1 - \sqrt{x}}{1 + \sqrt{x}}$ by $\frac{1 - \sqrt{x}}{1 - \sqrt{x}}$ .

$\frac{(1 - \sqrt{x}) (1 - \sqrt{x})}{(1 + \sqrt{x}) (1 - \sqrt{x})} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 3

Expand the denominator using the FOIL method.

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

Step 4

Simplify.

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Step 4.1

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{x}$ as $x^{\frac{1}{2}}$ .

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

Step 4.2

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

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

Step 4.3

Combine $\frac{1}{2}$ and $2$ .

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

Step 4.4

Cancel the common factor of $2$ .

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Step 4.4.1

Cancel the common factor.

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

Step 4.4.2

Rewrite the expression.

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

Step 4.5

Simplify.

$\frac{(1 - \sqrt{x}) (1 - \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 5

Simplify the numerator.

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Step 5.1

Raise $1 - \sqrt{x}$ to the power of $1$ .

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

Step 5.2

Raise $1 - \sqrt{x}$ to the power of $1$ .

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

Step 5.3

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

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

Step 5.4

Add $1$ and $1$ .

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

Step 6

Rewrite ${(1 - \sqrt{x})}^{2}$ as $(1 - \sqrt{x}) (1 - \sqrt{x})$ .

$\frac{(1 - \sqrt{x}) (1 - \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 7

Expand $(1 - \sqrt{x}) (1 - \sqrt{x})$ using the FOIL Method.

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Step 7.1

Apply the distributive property.

$\frac{1 (1 - \sqrt{x}) - \sqrt{x} (1 - \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 7.2

Apply the distributive property.

$\frac{1 \cdot 1 + 1 (- \sqrt{x}) - \sqrt{x} (1 - \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 7.3

Apply the distributive property.

$\frac{1 \cdot 1 + 1 (- \sqrt{x}) - \sqrt{x} \cdot 1 - \sqrt{x} (- \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8

Simplify and combine like terms.

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Step 8.1

Simplify each term.

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Step 8.1.1

Multiply $1$ by $1$ .

$\frac{1 + 1 (- \sqrt{x}) - \sqrt{x} \cdot 1 - \sqrt{x} (- \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.2

Multiply $- \sqrt{x}$ by $1$ .

$\frac{1 - \sqrt{x} - \sqrt{x} \cdot 1 - \sqrt{x} (- \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.3

Multiply $- 1$ by $1$ .

$\frac{1 - \sqrt{x} - \sqrt{x} - \sqrt{x} (- \sqrt{x})}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.4

Multiply $- \sqrt{x} (- \sqrt{x})$ .

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Step 8.1.4.1

Multiply $- 1$ by $- 1$ .

$\frac{1 - \sqrt{x} - \sqrt{x} + 1 \sqrt{x} \sqrt{x}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.4.2

Multiply $\sqrt{x}$ by $1$ .

$\frac{1 - \sqrt{x} - \sqrt{x} + \sqrt{x} \sqrt{x}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.4.3

Raise $\sqrt{x}$ to the power of $1$ .

$\frac{1 - \sqrt{x} - \sqrt{x} + {\sqrt{x}}^{1} \sqrt{x}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.4.4

Raise $\sqrt{x}$ to the power of $1$ .

$\frac{1 - \sqrt{x} - \sqrt{x} + {\sqrt{x}}^{1} {\sqrt{x}}^{1}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.4.5

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

$\frac{1 - \sqrt{x} - \sqrt{x} + {\sqrt{x}}^{1 + 1}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.4.6

Add $1$ and $1$ .

$\frac{1 - \sqrt{x} - \sqrt{x} + {\sqrt{x}}^{2}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.5

Rewrite ${\sqrt{x}}^{2}$ as $x$ .

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Step 8.1.5.1

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{x}$ as $x^{\frac{1}{2}}$ .

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

Step 8.1.5.2

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

$\frac{1 - \sqrt{x} - \sqrt{x} + x^{\frac{1}{2} \cdot 2}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.5.3

Combine $\frac{1}{2}$ and $2$ .

$\frac{1 - \sqrt{x} - \sqrt{x} + x^{\frac{2}{2}}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.5.4

Cancel the common factor of $2$ .

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Step 8.1.5.4.1

Cancel the common factor.

$\frac{1 - \sqrt{x} - \sqrt{x} + x^{\frac{2}{2}}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.5.4.2

Rewrite the expression.

$\frac{1 - \sqrt{x} - \sqrt{x} + x^{1}}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.1.5.5

Simplify.

$\frac{1 - \sqrt{x} - \sqrt{x} + x}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 8.2

Subtract $\sqrt{x}$ from $- \sqrt{x}$ .

$\frac{1 - 2 \sqrt{x} + x}{1 - x} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$

Step 9

Since the two sides have been shown to be equivalent, the equation is an identity.

$\frac{1 - \sqrt{x}}{1 + \sqrt{x}} = \frac{1 - 2 \sqrt{x} + x}{1 - x}$ is an identity.