Trigonometry Examples

$\frac{\tan (x) + \sec (x) - 1}{\tan (x) - \sec (x) + 1} = \tan (x) + \sec (x)$

Step 1

Start on the left side.

$\frac{\tan (x) + \sec (x) - 1}{\tan (x) - \sec (x) + 1}$

Step 2

Multiply $\frac{\tan (x) + \sec (x) - 1}{\tan (x) - \sec (x) + 1}$ by $\frac{- \tan (x) + \sec (x) + 1}{- \tan (x) + \sec (x) + 1}$ .

$\frac{\tan (x) + \sec (x) - 1}{\tan (x) - \sec (x) + 1} \cdot \frac{- \tan (x) + \sec (x) + 1}{- \tan (x) + \sec (x) + 1}$

Step 3

Combine.

$\frac{(\tan (x) + \sec (x) - 1) (- \tan (x) + \sec (x) + 1)}{(\tan (x) - \sec (x) + 1) (- \tan (x) + \sec (x) + 1)}$

Step 4

Simplify numerator.

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Step 4.1

Expand $(\tan (x) + \sec (x) - 1) (- \tan (x) + \sec (x) + 1)$ by multiplying each term in the first expression by each term in the second expression.

$\frac{\tan (x) (- \tan (x)) + \tan (x) \sec (x) + \tan (x) \cdot 1 + \sec (x) (- \tan (x)) + \sec (x) \sec (x) + \sec (x) \cdot 1 - 1 (- \tan (x)) - 1 \sec (x) - 1 \cdot 1}{(\tan (x) - \sec (x) + 1) (- \tan (x) + \sec (x) + 1)}$

Step 4.2

Simplify each term.

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Step 4.2.1

Multiply $\tan (x) (- \tan (x))$ .

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Step 4.2.1.1

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

$\frac{- ({\tan (x)}^{1} \tan (x)) + \tan (x) \sec (x) + \tan (x) \cdot 1 + \sec (x) (- \tan (x)) + \sec (x) \sec (x) + \sec (x) \cdot 1 - 1 (- \tan (x)) - 1 \sec (x) - 1 \cdot 1}{(\tan (x) - \sec (x) + 1) (- \tan (x) + \sec (x) + 1)}$

Step 4.2.1.2

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

$\frac{- ({\tan (x)}^{1} {\tan (x)}^{1}) + \tan (x) \sec (x) + \tan (x) \cdot 1 + \sec (x) (- \tan (x)) + \sec (x) \sec (x) + \sec (x) \cdot 1 - 1 (- \tan (x)) - 1 \sec (x) - 1 \cdot 1}{(\tan (x) - \sec (x) + 1) (- \tan (x) + \sec (x) + 1)}$

Step 4.2.1.3

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

$\frac{- {\tan (x)}^{1 + 1} + \tan (x) \sec (x) + \tan (x) \cdot 1 + \sec (x) (- \tan (x)) + \sec (x) \sec (x) + \sec (x) \cdot 1 - 1 (- \tan (x)) - 1 \sec (x) - 1 \cdot 1}{(\tan (x) - \sec (x) + 1) (- \tan (x) + \sec (x) + 1)}$

Step 4.2.1.4

Add $1$ and $1$ .

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

Step 4.2.2

Multiply $\tan (x)$ by $1$ .

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

Step 4.2.3

Multiply $\sec (x) \sec (x)$ .

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Step 4.2.3.1

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

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

Step 4.2.3.2

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

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

Step 4.2.3.3

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

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

Step 4.2.3.4

Add $1$ and $1$ .

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

Step 4.2.4

Multiply $\sec (x)$ by $1$ .

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

Step 4.2.5

Multiply $- 1 (- \tan (x))$ .

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Step 4.2.5.1

Multiply $- 1$ by $- 1$ .

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

Step 4.2.5.2

Multiply $\tan (x)$ by $1$ .

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

Step 4.2.6

Rewrite $- 1 \sec (x)$ as $- \sec (x)$ .

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

Step 4.2.7

Multiply $- 1$ by $1$ .

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

Step 4.3

Add $\sec (x) \tan (x)$ and $\sec (x) (- \tan (x))$ .

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Step 4.3.1

Reorder $\sec (x)$ and $- 1$ .

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

Step 4.3.2

Subtract $\sec (x) \tan (x)$ from $\sec (x) \tan (x)$ .

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

Step 4.4

Add $- {\tan (x)}^{2}$ and $0$ .

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

Step 4.5

Add $\tan (x)$ and $\tan (x)$ .

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

Step 4.6

Subtract $\sec (x)$ from $\sec (x)$ .

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

Step 4.7

Add $- {\tan (x)}^{2}$ and $0$ .

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

Step 5

Simplify denominator.

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Step 5.1

Expand $(\tan (x) - \sec (x) + 1) (- \tan (x) + \sec (x) + 1)$ by multiplying each term in the first expression by each term in the second expression.

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

Step 5.2

Simplify each term.

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Step 5.2.1

Multiply $\tan (x) (- \tan (x))$ .

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Step 5.2.1.1

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

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

Step 5.2.1.2

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

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

Step 5.2.1.3

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

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

Step 5.2.1.4

Add $1$ and $1$ .

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

Step 5.2.2

Multiply $\tan (x)$ by $1$ .

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

Step 5.2.3

Multiply $- \sec (x) (- \tan (x))$ .

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Step 5.2.3.1

Multiply $- 1$ by $- 1$ .

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

Step 5.2.3.2

Multiply $\sec (x)$ by $1$ .

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

Step 5.2.4

Multiply $- \sec (x) \sec (x)$ .

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Step 5.2.4.1

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

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

Step 5.2.4.2

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

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

Step 5.2.4.3

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

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

Step 5.2.4.4

Add $1$ and $1$ .

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

Step 5.2.5

Multiply $- 1$ by $1$ .

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

Step 5.2.6

Multiply $- \tan (x)$ by $1$ .

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

Step 5.2.7

Multiply $\sec (x)$ by $1$ .

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

Step 5.2.8

Multiply $1$ by $1$ .

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

Step 5.3

Add $\sec (x) \tan (x)$ and $\sec (x) \tan (x)$ .

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

Step 5.4

Subtract $\tan (x)$ from $\tan (x)$ .

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

Step 5.5

Add $- {\tan (x)}^{2}$ and $0$ .

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

Step 5.6

Add $- \sec (x)$ and $\sec (x)$ .

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

Step 5.7

Add $- {\tan (x)}^{2}$ and $0$ .

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

Step 6

Simplify the expression.

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Step 6.1

Move $\sec^{2} (x)$ .

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

Step 6.2

Reorder $- \tan^{2} (x)$ and $\sec^{2} (x)$ .

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

Step 6.3

Apply pythagorean identity.

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

Step 6.4

Factor $- 1$ out of $- \sec^{2} (x)$ .

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

Step 6.5

Rewrite $1$ as $- 1 (- 1)$ .

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

Step 6.6

Factor $- 1$ out of $- \sec^{2} (x) - 1 \cdot - 1$ .

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

Step 6.7

Apply pythagorean identity.

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

Step 6.8

Simplify the numerator.

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Step 6.8.1

Rewrite $\tan (x)$ in terms of sines and cosines.

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

Step 6.8.2

Combine $2$ and $\frac{\sin (x)}{\cos (x)}$ .

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

Step 6.8.3

Subtract $1$ from $1$ .

$\frac{0 + \frac{2 \sin (x)}{\cos (x)}}{- \tan^{2} (x) + 2 \sec (x) \tan (x) - \tan^{2} (x)}$

Step 6.8.4

Add $0$ and $\frac{2 \sin (x)}{\cos (x)}$ .

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

Step 6.9

Simplify the denominator.

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Step 6.9.1

Subtract $\tan^{2} (x)$ from $- \tan^{2} (x)$ .

$\frac{\frac{2 \sin (x)}{\cos (x)}}{2 \sec (x) \tan (x) - 2 \tan^{2} (x)}$

Step 6.9.2

Factor $2 \tan (x)$ out of $2 \sec (x) \tan (x) - 2 \tan^{2} (x)$ .

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Step 6.9.2.1

Factor $2 \tan (x)$ out of $2 \sec (x) \tan (x)$ .

$\frac{\frac{2 \sin (x)}{\cos (x)}}{2 \tan (x) (\sec (x)) - 2 \tan^{2} (x)}$

Step 6.9.2.2

Factor $2 \tan (x)$ out of $- 2 \tan^{2} (x)$ .

$\frac{\frac{2 \sin (x)}{\cos (x)}}{2 \tan (x) (\sec (x)) + 2 \tan (x) (- \tan (x))}$

Step 6.9.2.3

Factor $2 \tan (x)$ out of $2 \tan (x) (\sec (x)) + 2 \tan (x) (- \tan (x))$ .

$\frac{\frac{2 \sin (x)}{\cos (x)}}{2 \tan (x) (\sec (x) - \tan (x))}$

Step 6.9.3

Rewrite $\sec (x)$ in terms of sines and cosines.

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

Step 6.9.4

Rewrite $\tan (x)$ in terms of sines and cosines.

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

Step 6.9.5

Rewrite $\tan (x)$ in terms of sines and cosines.

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

Step 6.9.6

Combine $2$ and $\frac{\sin (x)}{\cos (x)}$ .

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

Step 6.10

Cancel the common factor of $\frac{2 \sin (x)}{\cos (x)}$ .

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Step 6.10.1

Cancel the common factor.

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

Step 6.10.2

Rewrite the expression.

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

Step 7

Simplify.

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Step 7.1

Combine the numerators over the common denominator.

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

Step 7.2

Multiply the numerator by the reciprocal of the denominator.

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

Step 7.3

Multiply $\frac{\cos (x)}{1 - \sin (x)}$ by $1$ .

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

Step 8

Multiply $\frac{\cos (x)}{1 - \sin (x)}$ by $\frac{1 + \sin (x)}{1 + \sin (x)}$ .

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

Step 9

Combine.

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

Step 10

Simplify numerator.

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Step 10.1

Apply the distributive property.

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

Step 10.2

Multiply $\cos (x)$ by $1$ .

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

Step 11

Simplify denominator.

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Step 11.1

Expand $(1 - \sin (x)) (1 + \sin (x))$ using the FOIL Method.

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Step 11.1.1

Apply the distributive property.

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

Step 11.1.2

Apply the distributive property.

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

Step 11.1.3

Apply the distributive property.

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

Step 11.2

Simplify and combine like terms.

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

Step 12

Apply pythagorean identity.

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

Step 13

Simplify.

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Step 13.1

Factor $\cos (x)$ out of $\cos (x) + \cos (x) \sin (x)$ .

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Step 13.1.1

Multiply by $1$ .

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

Step 13.1.2

Factor $\cos (x)$ out of $\cos (x) \sin (x)$ .

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

Step 13.1.3

Factor $\cos (x)$ out of $\cos (x) \cdot 1 + \cos (x) (\sin (x))$ .

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

Step 13.2

Cancel the common factors.

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

Step 14

Now consider the right side of the equation.

$\tan (x) + \sec (x)$

Step 15

Convert to sines and cosines.

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Step 15.1

Write $\tan (x)$ in sines and cosines using the quotient identity.

$\frac{\sin (x)}{\cos (x)} + \sec (x)$

Step 15.2

Apply the reciprocal identity to $\sec (x)$ .

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

Step 16

Combine the numerators over the common denominator.

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

Step 17

Reorder terms.

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

Step 18

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

$\frac{\tan (x) + \sec (x) - 1}{\tan (x) - \sec (x) + 1} = \tan (x) + \sec (x)$ is an identity