Homework Help: Double integrals using polar co-ordinates

1. Nov 3, 2012

Mdhiggenz

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

Step 1) I put the following into polar coordinates
√(16-x2-y2)=√16-r2

Where r≤4

step 2 I solved for y in the original problem which is in the link

y≤√(4-x2)

step 3. I graphed the above function

step 4. I put the above function in polar coordinates getting

r≤2

So I already had an idea that the graph would be from

0≤r≤2 dr However my d(theta) was incorrect I got that it would be 0≤theta≤∏ as my interpretation of the graph shows. The answer however shows 0≤theta≤2∏

Which does't make much sense to me. Where did I got wrong?

2. Relevant equations

3. The attempt at a solution

2. Nov 3, 2012

tiny-tim

what is the actual question?

3. Nov 3, 2012

Mdhiggenz

Upper left hand corner of the graph, the problem statement says Use a multiple integral and a convenient coordinate system to find the volume of the solid. I forgot to type it up I apologize.

4. Nov 3, 2012

tiny-tim

i still don't get it

x2+ y2 ≤ 4 isn't a circle, it's a solid cylinder

anyway, show us how you found the line of interection​

5. Nov 3, 2012

Mdhiggenz

Honestly I don't know I solved as if it was a circle.