What is the volume obtained by rotating the region enclosed by y=11x, y=3x+7, and x=0 about the y-axis?

1 Answer
Mar 27, 2016

V=V1V2=11,525π27
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Explanation:

Given: y=11x, y=3x+7, and x=0
Required: The volume obtained by rotating about the y-axis
Solution strategy: looking at the figure we see that

V=2π[111x(11x)dx1213x(3x+7)dx]

V1=2π[(112x2x33)111]
V2=2π[(x3+7x22)1213]
V=V1V2=11,525π27