Question

Evaluate Sin^-1 (1) without a calculator. Express Answer in Radians and Degrees.

Answer 1

Use unit circle look at values between -pi/2 and pi/2 (inclusive)
such that sin(?)=1

What is ?

Answer 2

Sin, on a unit circle, is the y value of the coordinate (this is because Sin is y/r and r is 1).


All you have to do now is find the angles where the y coordinate of that point is 1. Notice that it is at 90 degrees, or \(\frac{\pi}{2}\).