Answer
$0.46, 3.61$
Work Step by Step
The domain of $\tan^{-1}{x}$ is the range of $\tan{x}$, which is the real numbers.
The range of $\tan^{-1}{x}$ is a specified domain of $\tan{x}$, i.e. $\left(− \frac{\pi}{2} , \frac{\pi}{2} \right)$.
We know that $\cot^{-1}(x)=\tan^{-1}{\frac{1}{x}}$.
After using a calculator in radian mode the solutions for $\theta=\cot^{-1}{2}=\tan^{-1}{\frac{1}{2}}=0.463647609\approx0.46$ (given by the calculator) and because the cotangent function has a period of $\pi$, the second solution is: $0.463647609+\pi\approx 3.61$.
