I'm having a lot of problems with these questions.
Volume of the region enclosed by y^2=4x and y=x about the line x=4
I can graph it, but I can't set up the integral.
Another one is "The base of a solid is a the region enclosed between the graphs of y=sinx and y=-sinx from x=0 to x=pi. Each cross section perpendicular to the x-axis is a semicircle with diameter connecting the two graphs. Find the volume."
I just don't know what to do with the information it gives me in the second sentence.