How do you show that #cos 2theta = 1-2sin^2 theta# ?
1 Answer
Apr 20, 2016
See explanation...
Explanation:
Given that:
#cos 2theta = cos^2 theta - sin^2 theta#
and:
#cos^2 theta + sin^2 theta = 1#
we find:
#cos 2theta = (1 - sin^2 theta) - sin^2 theta =1 - 2 sin^2 theta#
