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

I've been having problems with a lot of identity problems lately, but I've found that I'm especially having issues with problems like this one;

Verify the identity,

1/2 Sin (4x) = 2SinxCosx-4Sin^{3}xCosx

2. Relevant equations

My professor told me you use Sin(A-B)=SinACosB-CosASinB

3. The attempt at a solution

The best I could do was

1/2 Sin4x=2SinxCox-4Sin^{3}xCos

1/2Sin4x=2(SinxCosx-2sin^{3})

1/2Sin4x=2Sin(x-4x)=-2Sin(3x)

I know that this is a horrible attempt at solving, but some help would be greatly appreciated.

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# Homework Help: Double-Angle Simplification

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