# Homework Help: 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.