Precalculus Examples

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

Step 1

Expand $(\sec (x) - \tan (x)) (\sec (x) + \tan (x))$ using the FOIL Method.

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Step 1.1

Apply the distributive property.

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

Step 1.2

Apply the distributive property.

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

Step 1.3

Apply the distributive property.

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

Step 2

Simplify terms.

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Step 2.1

Combine the opposite terms in $\sec (x) \sec (x) + \sec (x) \tan (x) - \tan (x) \sec (x) - \tan (x) \tan (x)$ .

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Step 2.1.1

Reorder the factors in the terms $\sec (x) \tan (x)$ and $- \tan (x) \sec (x)$ .

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

Step 2.1.2

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

$\sec (x) \sec (x) + 0 - \tan (x) \tan (x)$

Step 2.1.3

Add $\sec (x) \sec (x)$ and $0$ .

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

Step 2.2

Simplify each term.

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Step 2.2.1

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

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Step 2.2.1.1

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

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

Step 2.2.1.2

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

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

Step 2.2.1.3

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

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

Step 2.2.1.4

Add $1$ and $1$ .

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

Step 2.2.2

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

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Step 2.2.2.1

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

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

Step 2.2.2.2

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

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

Step 2.2.2.3

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

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

Step 2.2.2.4

Add $1$ and $1$ .

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

Step 3

Apply pythagorean identity.

$1$