(Nevermind) Establish Trig Identity: Sums to Products

[veganazi]

Homework Statement

Establish the identity: 1+cos(2θ)+cos(4θ)+cos(6θ)=4cosθcos(2θ)cos(3θ)

Homework Equations

cos(a)+cos(b)=2cos((a+b)/2)cos((a-b)/2)

The Attempt at a Solution

I understand how to do a simple cos(+/-)cos problem according to the Sums as Products equations, but I am confused on how to handle adding 3 cosine functions plus 1.

EDIT: cos(0)=1, so I split the problem into 2 additions problems, cos(0θ)+cos(2θ) and cos(4θ)+cos(6θ).

 

[susskind_leon]

So you figured it out already?