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Homework Statement
the directions are:
compute the volume of the solid formed by revolving the given region about the line
region bounded by y=2x, y=2 and x=0 about (a) the y-axis; (b) x=1
Homework Equations
V=∫A(x)dx,a,b
The Attempt at a Solution
From what my teacher showed in class this is how i think it is worked out
(a)
V=∫A(x)dx,0,2
=∫(pi)[r(x)]^2,0,2
=∫(pi)[2x-2]^2,0,2
=∫(pi)[4x^2-a],0,2
=(8(pi))/3
so i am not sure if this is right or if i have to times(8(pi))/3 by 1/3 because the volume of a cone is (1/3)(pi)(r^2)(h)
and i don't know where to begin on (b), i think when it is revolved it will be Cylinder with a cut out. please help