Saturday, September 28, 2013

`y = root(3)(x), y = 0, x = 1` Use the method of cylindrical shells to find the volume generated by rotating the region bounded by the given...

The shell has the radius `x` , the cricumference is `2pi*x ` and the height is `root(3)(x)` , hence, the volume can be evaluated, using the method of cylindrical shells, such that:


`V = 2pi*int_(x_1)^(x_2) x*(6x - 3x^2) dx`


You need to evaluate the endpoints `x_1` and `x_2` , such that:


`root(3) x = 0 => x = 0^3 =>x = 0`


`V = 2pi*int_0^1 x*(root(3) x) dx`


`V = 2pi*(int_0^1 x^(1/3) dx`


Using the formula `int x^n dx = (x^(n+1))/(n+1)` yields:


`V = 2pi*(3/4)*(x^(4/3))|_0^1`


`V = (3pi/2)*(1^(4/3) - 0^(4/3))`


`V = (3pi)/2`


Hence, evaluating the volume, using the method of cylindrical shells, yields `V = (3pi)/2.`

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