Precalculus Examples

$f (x) = x^{2} + 6$

Step 1

Find $f (- x)$ .

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Find $f (- x)$ by substituting $- x$ for all occurrence of $x$ in $f (x)$ .

$f (- x) = {(- x)}^{2} + 6$

Simplify each term.

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Apply the product rule to $- x$ .

$f (- x) = {(- 1)}^{2} x^{2} + 6$

Raise $- 1$ to the power of $2$ .

$f (- x) = 1 x^{2} + 6$

Multiply $x^{2}$ by $1$ .

$f (- x) = x^{2} + 6$

Step 2

A function is even if $f (- x) = f (x)$ .

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Check if $f (- x) = f (x)$ .

$x^{2} + 6 = x^{2} + 6$

Since $x^{2} + 6 = x^{2} + 6$ , the function is even.

The function is even

Step 3