Since you are squaring the integrand the order does not matter but it is best to think of this as
As you said since you didn't show your steps I don't know where the error occurred.
The diagram shows part of the curves ' ' and
a.) Find the coordinates of A ( A is where they intercept in the top right of the diagram)
b.) Calculate the volume generated when the area enclosed by the curve is rotated through 360(degrees) about the x axis.
I identified A to be (2,4).
Then to attempt the 'b' part of my question
Using this I get a result of which is incorrect. Wondering if you can see my error. Sorry for the lack of steps, I'm having difficulty with LATEX (I'm in the process of improving though).