Can someone who's actually going to answer rather than say random stuff help me?

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

What is the measure of angle tvu shown in the diagram below

A(1,1) b(-3,0) c(-4,-1) d(3,-2) drag it to correct position