Find the volume generated by the rotation about the $Y-axis$ of the area between the curves in the first and fourth quadrant $y=x^2-1$ and $y=3-x^2$ using method of cylindrical shells.
Now height of shell is $(x^2-1)-(3-x^2)$ but what will be the radius? Will it be $x$? What should be kept in mind in such questions to obtain radius.
