Evaluate cos(arccos((32pi)/3)) (I think I know how, just need someone to confirm)

1. Feb 26, 2012

Ianfinity

Evaluate cos(arccos((32pi)/3))

From my understanding, I need to subtract (32pi)/3 by pi until the answer falls within the domain of [-1, 1]. Is this the correct way to solve this problem?

2. Feb 26, 2012

D H

Staff Emeritus
Are you sure you don't mean $\arccos(\cos(\frac{32\pi}3))$ instead of $\cos(\arccos(\frac{32\pi}3))$ ?

3. Feb 27, 2012

Ianfinity

Yes, I am sure. It IS possible, however, that the problem has no solution, if that's what you're getting at.

4. Feb 27, 2012

Ansatz7

What is the domain of arccos? Also, this shouldn't be in the "Calculus and Beyond" section of the forum...

5. Feb 27, 2012

SammyS

Staff Emeritus
No. That's not the way to solve this.

See Ansatz7's post above.