Question

Write the principal value of \(tan^{-1}(-1)\).

Answer 1

\(\therefore\) Principal value of \(tan^{-1}(-1)\) is \(-\frac{\pi}4.\)

[\(\therefore\) \(-\frac{\pi}4\in(-\frac\pi{2},\frac{\pi}2)\) range of the principal value branch of \(tan^{-1}\) function and tan\((-\frac{\pi}4)=-1\)]