Consider the region bounded by y=x^2, y=1, and the y-axis, for x greater than or equal to 0. Find the volume of the solid obtained by rotating the region about the line y=-7.

I know that its a parabola making a sort of oblong shape when rotated and that it can only be solved via the washer method, but every answer I come up with for the inner and outer radii has turned out to be wrong. Anyone else have any ideas?

Question

Consider the region bounded by y=x^2, y=1, and the y-axis,  for x greater than or equal to 0. Find the volume of the solid obtained by rotating the region about the line y=-7.

I know that its a parabola making a sort of oblong shape when rotated and that it can only be solved via the washer method, but every answer I come up with for the inner and outer radii has turned out to be wrong. Anyone else have any ideas?

triciaal · Answer

i can't say i have the solution but hoping this sketch will help and the outer radius would be 8|dw:1403818701216:dw|