they intersect at (0,0) and when
.5x^2 = x
x^2 - 2x = 0
x(x-2) = 0
x = 0 or x = 2, then y = 0 or y = 2
at (0,0) and (2,2)
the disc will look like a washer,
outer radius = 7- y
inner radius = 7- √(2y)
volume = π∫( (7 - y)^2 - (7- √(2y))^2 ) dy from 0 to 2
expand (7 - y)^2 - (7- √(2y))^2 , integrate etc.
Write the integral in one variable to find the volume of the solid obtained by rotating the first-quadrant region bounded by y = 0.5x^2 and y = x about the line x = 7.
I have to use the volume by disks method, but I'm confused about how to set it up and evaluate
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