How do you prove cos2x=1-2sin^2x using other trigonometric identities?
1 Answer
Mar 1, 2016
see explanation
Explanation:
Using
color(blue)" Double angle formula "
• cos2x = cos^2 x - sin^2 x and the identity
cos^2x = 1 - sin^2x
rArrcos2x = cos^2x - sin^2x = (1-sin^2x) - sin^2x
= 1 - 2sin^2x = " right hand side " hence proved.