Write the expression and evaluate. There is only one answer whIch should match the range of the inverse trig function.

Question

Sec^-1(-2)

I got 2pi/3
could someone tell me if that is right? And if not, could someone please explain how to get the answer.

Answer 1

if the sec is -2 then the cos is -1/2

that would be 180- 60 or pi - pi/3 = 2pi/3