# Volume ( is the set up OK?)

1. Sep 22, 2013

### Jbreezy

1. The problem statement, all variables and given/known data

Find the volume obtained by rotating the regon boudned by the given curve about the specified axis

2. Relevant equations

3. The attempt at a solution

y = secx, y = cosx, 0 <= x < = pi/3

This is what I set up.

V = ∏∫ (secx +1 )^2 - (cosx +1)^2 dx

I said R was secx - (-1) and r is cosx -(-1)

2. Sep 22, 2013

### Staff: Mentor

Looks OK, assuming you are rotating the region about the line y = -1, which is info you didn't provide. When you post a problem, remember to include the complete problem statement.

3. Sep 22, 2013

### Jbreezy

Yeah I'm doing it about x = -1. Thanks dude. Sorry.

4. Sep 22, 2013

### arildno

Why the 1's?
The radii in the cross-sectional disks are specified with the function values.
Thus, your integrand is sec^2(x)-cos^2(x)

I assumed it was about y=0

5. Sep 22, 2013

### Jbreezy

Yeah well that is because I made a mistake in my post and left out that is was about y = -1.

6. Sep 22, 2013

### Staff: Mentor

Apparently you aren't clear, either.

7. Sep 22, 2013

### Jbreezy

Ha. Lack of sleep