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
Nghi N
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#

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