Use the method of cylindrical shells to find the volume generated by rotating the region bounded by the given curves about the specified axis:
y= x^2 , y = 2 - x^2 ; rotated about x = 1
Any and all help is much appreciated! Thanks so much in advance!
y= x^2 , y = 2 - x^2 ; rotated about x = 1
Any and all help is much appreciated! Thanks so much in advance!
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Hello
Both curves intersect at x = -1 and +1. So you should integrate from -1 to +1. But if you shift the curves to the right by one unit, you can rotate around the y axis. And this is then identical to rotating the original curves around x = 1, because both original curves are symmetrical to the y axis.
f(x) = 2 - (x-1)^2 is the upper curve, and g(x) = (x-1)^2 the lower one.
Use
V = 2pi∫(x(f(x) - g(f))dx
V = 2pi*∫(x*(2 - (x-1)^2 - (x-1)^2) dx from x = 0 to 2
V = 2pi*∫(x*(2 - 2(x-1)^2))dx
extend and integrate:
V = 16,7552
Regards
2pi∫(x(2-2(x-1)^2))dx
= 2pi[-1/2*x^4+4/3*x^3]
Both curves intersect at x = -1 and +1. So you should integrate from -1 to +1. But if you shift the curves to the right by one unit, you can rotate around the y axis. And this is then identical to rotating the original curves around x = 1, because both original curves are symmetrical to the y axis.
f(x) = 2 - (x-1)^2 is the upper curve, and g(x) = (x-1)^2 the lower one.
Use
V = 2pi∫(x(f(x) - g(f))dx
V = 2pi*∫(x*(2 - (x-1)^2 - (x-1)^2) dx from x = 0 to 2
V = 2pi*∫(x*(2 - 2(x-1)^2))dx
extend and integrate:
V = 16,7552
Regards
2pi∫(x(2-2(x-1)^2))dx
= 2pi[-1/2*x^4+4/3*x^3]