Write in simplest form:

3cos^-1x = cos^-1(4x^3 - 3x) x belongs to [1/2, 1]

Please help me find the answer! I'm not sure if replacing the value of x with cos theta will help(I've never heard of cos3x = 4cos^3x- 3cosx)

Does that exist?

Question

Write in simplest form:

3cos^-1x = cos^-1(4x^3 - 3x) x belongs to [1/2, 1]

Please help me find the answer! I'm not sure if replacing the value of x with cos theta will help(I've never heard of cos3x = 4cos^3x- 3cosx)

Does that exist?

anonymous · Answer

@zepdrix help me? :(

zepdrix · Answer

Hmm brb :d

anonymous · Answer

Alright take your time, I'll be doing the other questions :)

zepdrix · Answer

Ahhh the 3 is confusing me!! >.<
So how were you able to make that conversion?
You let $\Large\rm x=\cos\theta$ and then somehow got that equation in the parenthesis?

anonymous · Answer

Yeah I replaced x value as cos theta.. it says in my textbook that its the way to do it