Sin^2(x)-cos^2(x)= sin^2(x)+cos^2(x) Find exact solutions between 0 and 2π How should I solve this?

1 Answer
May 26, 2017

pi/2 ; (3pi)/2

Explanation:

sin^2 x - cos^2 x = sin^2 x +cos^2 x = 1
Replace cos^2 x by (1 - sin^2 x):
sin^2 x - 1 + sin^2 x = 1
2sin^2 x =2 --> sin^2 x = 1 -->
sin x = +- 1
Unit circle gives -->
x = pi/2 and x = (3pi)/2