The principal value of $\cot ^{-1}\left(\frac{-1}{\sqrt{3}}\right)$ is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $\frac{2 \pi}{3}$
$\cot^{-1}\left(\frac{-1}{\sqrt{3}}\right)=π-\cot^{-1}\left(\frac{-1}{\sqrt{3}}\right)$
$=π-\frac{π}{3}=\frac{2π}{3}$