Which integral correctly computes the volume formed when the region bounded by the curves x2 + y2 = 25, x = 3 and y = 0 is rotated around the y-axis?

HELP PLEASE

Question

Which integral correctly computes the volume formed when the region bounded by the curves x2 + y2 = 25, x = 3 and y = 0 is rotated around the y-axis?

HELP PLEASE

jtvatsim · Answer

Have you sketched it out for yourself? I'm beginning to sketch it for myself right now.

anonymous · Answer

yes I have

jtvatsim · Answer

From what I'm getting the bounded area is sort of like a pie slice, and the volume looks like a doughnut or something. It's got a big hole through the center.

jtvatsim · Answer

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anonymous · Answer

i know the intefral has sqrt 25-y^2 in it

jtvatsim · Answer

Yes, that's a good start. We need to take into account the hole as well in order to get the correct integral.

jtvatsim · Answer

Our slices are basically "washers" or cylinders with holes. From above, the slices look like this:

jtvatsim · Answer

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