## Precalculus (10th Edition)

$\approx-0.25.$
I know that $\cot x=\frac{1}{\tan(x)}$, hence $\cot^{-1}x=\tan^{-1} \frac{1}{x}$. I use a calculator in radian mode and then round the result, hence: $\cot^{-1}{(-4)}=\tan^{-1}{-\frac{1}{4}}=-0.2450\approx-0.25.$