Question

The domain of $f\left(x\right)=co{t}^{-1}\left(\frac{x}{3}\right)$ is

• A. $(-\infty ,\infty )$
• B. $(0,\infty )$
• C. $(1,\infty )$
• D. $\left(-\frac{1}{3},\frac{1}{3}\right)$

Answer 1

Answer: (A)

$(-\infty ,\infty )$

${\cot }^{-1}$ is defined for all $x$
$\therefore$ Domain of $f$ is $(-\infty ,\infty )$