Question

Find the exact value of arcsin(-1) without using a calculator.

A. 2pi/3
B. - pi/3
C. 0
D. - pi/2
E. - pi/6

Answer 1

-pi/2 since \[sin(-\frac{\pi}{2})=-1\]

Answer 2

Again, a special trig value.
sin(-pi/2) = -1 since sin is negative in the third and fourth quadrants only.