Thread: Multi - Step Integral Problem

Problem
f(x) =
R is the area under the curve from 0 to 1.


Part A: Write down an integral that represents the volume of this solid using the slice method, rotating around the x-axis.

For this part I got an answer that I am pretty sure is right:

Part B: Write down the integral that represents the volume of this solid using the shell method, rotating around the x-axis.

For this part I put f(x) in terms of y and I got

Part C: The integral you obtain in part (b) should be an integral in y. Now making the substitution y = f(x) show that the integral in part (b) is equal to:


Using the substitution I got everything but the negative sign on the outside.

Part C(2): Hence, show that the integral in part (b) is equal to

I did use using the chain rule, d(f^2) = 2f(x) and then the two integrals are the same.
Part D: Using part (c), show that the integral in part (b) is equal to the integral in part (a).

No idea what to do

Thanks so much for the help