Determine the volum of a solid of revolution when the region bounded by and the straight lines y = 2 and x = 0 are rotated around the line x = 4

my answer(which is wrong)

??

what am I doing wrong?

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- April 11th 2011, 10:48 AMbijosnVolume of a solid of revolution bounded by
Determine the volum of a solid of revolution when the region bounded by and the straight lines y = 2 and x = 0 are rotated around the line x = 4

my answer(which is wrong)

??

what am I doing wrong? - April 11th 2011, 12:16 PMUnknown008
When you rotate about the x-axis (y = 0), you integrate with respect to x.

When you rotate along the line x = 4, you integrate with respect to y.

And can you tell why you picked ? - April 11th 2011, 12:21 PMProve It
Hint: Translate your function and all the bounds left 4 units. The region does not change, but the calculations are easier because you can rotate around the x axis.