(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

sin4x-sin2x/sin2x=cos3x/cosx

2. Relevant equations

sin2x = 2sinxcosx

3. The attempt at a solution

LS = sin(2x + 2x) - sin2x/sin2x

= sin2xcos2x + cos2xsin2x - sin2x/sin2x

= 2sin2xcos2x - sin2x/sin2x

This is where i get stuck...

I don't know what happens if you try to: 2sinx2x - sin2x or 2sin2x/sin2x, is that possible or not? Can you guys help me solve this question? Thanks.

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

Dismiss Notice

Join Physics Forums Today!

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

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

# Homework Help: Confused about double angle identities

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