The following problem has stumped me:
The region is bounded by the graphs of y=$\sqrt{x}$, $y=0$, and $x= 4$. Find the volume of a solid found by rotating the region about the axis $x=6$.
The outer boundary I choose was $(6-y^2)$ but have no idea on how to write the expression of the inner boundary.
More important than the answer could you please explain why and which outer and inner edges we will choose.
Also I have been trying to integrate with respect to the $y-axis$, because $x=6$ is parallel to it. Is that correct?
Here is a picture of one of the washers obtained. This is what I meant in my comment.