The base of a solid region in the first quadrant is bounded by the x-axis,y-axis, the graph of y=x^2+1y=x2+1, and the vertical line x=2. If the cross sections perpendicular to the x-axis are squares, what is the volume of the solid?

1 Answer
Jun 24, 2016

= 206/15=20615

Explanation:

the square cross section has sides of length y = (x^2 + 1)y=(x2+1)

so at any point xx, the cross sectional area A(x) is:

A(x) = ( x^2 + 1)^2A(x)=(x2+1)2

thus the volume is

V = int_0^2 \ A(x) \ dx = int_0^2 \ ( x^2 + 1)^2 \ dx

= int_0^2 \ x^4 + 2 x^2 + 1 \ dx

= [ x^5/5 + 2/3 x^3 + x ]_0^2

= [ 2^5/5 + 2/3 2^3 + 2 ]_0^2

= 206/15