Use the method of cylindrical shells to find the volume of the solid generated by rotating the region bounded by the curves y=cos(πx/2), y=0, x=0, and x=1 about the y-axis

Respuesta :

Answer:

1,45 cubic units

Step-by-step explanation:

The method of cylindrical shells demands that the volume of the solid is given by:

[tex]V=2\pi\int_a^b xf(x)dx[/tex]       (1)

In this case you have that f(x) is:

[tex]f(x)=cos(\frac{\pi}{2}x)[/tex]

a = 0

b = 1

First, you solve the integral, by parts:

[tex]\int xf(x)dx=\int xcos(\frac{\pi}{2}x)dx=x(\frac{2}{\pi})sin(\frac{\pi}{2}x)-\int (\frac{2}{\pi})sin(\frac{\pi}{2}x)dx\\\\=(\frac{2}{\pi})xsin(\frac{\pi}{2}x)+(\frac{2}{\pi})^2cos(\frac{\pi}{2}x)+C[/tex]

Next, you calculate the volume of the solid, by replacing the solution to the integral in the equation (1):

[tex]V=2\pi[(\frac{2}{\pi})xsin(\frac{\pi}{2}x)+(\frac{2}{\pi})^2cos(\frac{\pi}{2}x)]_0^1\\\\V=2\pi[(\frac{2}{\pi})-(\frac{2}{\pi})^2]=1,45u^3[/tex]

hence, the volume of the solid generated is 1,45 cubic units

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