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Let S be the solid obtained by rotating the region shown in the figure about the

ID: 2845005 • Letter: L

Question

Let S be the solid obtained by rotating the region shown in the figure about the y-axis. (Assume a=6 and b=2) be sure to answer all parts.

Sketch a typical approximating shell.



What are its circumference c and height h?
c(x) =
h(x) =

Use shells to find the volume V of S.
V =


Let S be the solid obtained by rotating the region shown in the figure about the y - axis. (Assume a = 6 and b = 2) be sure to answer all parts. Sketch a typical approximating shell. What are its circumference c and height h? Use shells to find the volume V of S.

Explanation / Answer

Circumference is 2pi x.

Height is 6x (x-2)^2

integral is 2pi int x * 6x (x-2) dx from x=0 to x=2

2pi int (6x^4 -24x^3 +24x^2) dx

Antiderivative is 6/5 x^5 - 6x^4 +8x^3

Evaluate from 0 to 2 and we have 2pi *32/5 = 64pi/5.