Cracking The Ap Calculus ab Exam 2018

(Marvins-Underground-K-12) #1
Our integral    for the area    is

Evaluating the integral, we get


(b) Find the volume of the solid generated when R is revolved about the x-axis.


In order to find the volume of a region between y = f (x) and y = g(x), from x = a to x = b,
when it is revolved around the x-axis, we use the following formula:


Here, our integral for the area is


Evaluating the integral, we get


(c) The section of a certain solid cut by any plane perpendicular to the x-axis is a circle with


the endpoints   of  its diameter    lying   on  the parabolas   y^2     =   x   and x^2     =   y.  Find    the volume  of  the
solid.

Whenever we want to find the volume of a solid, formed by the region between y = f(x) and y
= g(x), with a known cross-section, from x = a to x = b, when it is revolved around the x-axis,
we use the following formula:


(Note: A(x) is the area of the cross-section.) We find the area of the cross-section by using the

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