Determine the volume of the solid formed by rotation about the x-axis of the region bounded by the curves y=4^x-1 and y = 21x on the interval 0<x<3.

Verify this equation, y = 4^x-1

You need parentheses.

Is it, y = 4^(x - 1)?
Or, y = 4^(x) - 1?
Or ?

Are you Jamal? Please don't change screen names.

And, which is it? In this problem, rotation is about the x-axis. In the 'Jamal' problem, rotation is about the y-axis.