Precalculus Examples

$f (x) = {\begin{cases} 2 x - 2 & x \neq 4 \\ 4 & x = 4 \end{cases}$ Find $f (4)$

Step 1

Identify the piece that describes the function at $x = 4$ . In this case, $x = 4$ falls within the interval $x = 4$ , therefore use $4$ to evaluate $f (4)$ .

$f (x) = {\begin{cases} 2 x - 2 & x \neq 4 \\ 4 & x = 4 \end{cases}$

Step 2

The function is equal to $4$ at $x = 4$ .

$f (x) = 4 (]_{x = 4}^{})$

Step 3

Evaluate the function at $x = 4$ .

$f (4) = 4$