Why ##\sin^2 2x + \cos^2 2x = 1##?(adsbygoogle = window.adsbygoogle || []).push({});

Will

##\sin^2 3x + \cos^2 3x##

or

##\sin^2 4x + \cos^2 4x##

and so on, be = 1?

How to proof this?

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Trigonoemtric Identity

**Physics Forums | Science Articles, Homework Help, Discussion**