Question

For -1 < x < 1, by sketching a triangle, find cos^{-1} x + sin^{-1}x = _____ degrees.

Answer 1

Let's check for x=1/2
Cos^{-1} 1/2 + sin ^{-1} 1/2
=π/3+π/6=π/2
And this is true for every value of x from -1 to 1..
So answer is π/2 or 90°

Answer 2

@Kimes