#### Question

Find the principal value of tan^{−1} (−1)

#### Solution

Let tan^{−1} (−1) = *y*. Then tan y = -1 = `-tan (pi/4) = tan (-pi/4)`

We know that the range of the principal value branch of tan^{−1} is

`(-pi/2, pi/2) and tan(-pi/4) = - 1`

Therefore, the principal value of `tan^(-1) (-1) " is " pi/4`

Is there an error in this question or solution?

Solution Find the Principal Value of Tan^−1 (−1) Concept: Basic Concepts of Trigonometric Functions.