Answer
$\approx-1.11$
Work Step by Step
We know that $\cot {x}=\dfrac{1}{\tan{(x)}}$.
This can also be written as: $\cot^{-1}{x}=\tan^{-1} {\left(\frac{1}{x}\right)}$.
In order to get the answer in radians, we need to set the calculator in radians mode and round the result to two decimal places to obtain:
$\cot^{-1}{(-\dfrac{1}{2})}=\tan^{-1} (\dfrac{1}{-\dfrac{1}{2}})\approx-1.11$
