Writing as a function of only cosine without any powers of cosine

Hi, can anybody help me on this problem? Thanks in advance ^^

Write Cos^3(2θ) * Sine^2(2θ) as a function of only cosine without any powers of cosine.

Re: Writing as a function of only cosine without any powers of cosine

I would begin with:

Now, apply the double-angle identity for sine to the second factor...what do you get?

Re: Writing as a function of only cosine without any powers of cosine

Quote:

Originally Posted by

**DarkFlambe** Hi, can anybody help me on this problem? Thanks in advance ^^

Write Cos^3(2θ) * Sine^2(2θ) as a function of only cosine without any powers of cosine.

Re: Writing as a function of only cosine without any powers of cosine

Thanks! This helped a lot~