Question

Which of the following is not a reciprocal function?

• A. $f\left(x\right)=\frac{1}{x}$
• B. $f\left(x\right)=x^{-1}$
• C. $f\left(x\right)=x$
• D. None of the above

Answer 1

The correct option is C $f\left(x\right)=x$

This is the reciprocal function:

$f\left(x\right)=\frac{1}{x}$

Its domain is the real numbers, except $0$, because $\frac{1}{0}$ is undefined.

The reciprocal function can also be written as an exponent.

$f\left(x\right)=x^{-1}$