Rotational Volume - spherical cap, solids, and napkin ring problems

[emc92]

We are doing rotational volume in Calculus II right now. I know the basic rules for the disk, washer, and shell methods, but I'm having trouble getting started with these questions. I'm not sure how to set up the equations. Any sort of help would be great.

Thanks so much!

 

[Jet1045]

For the first and third example i have no clue. I am doing this same stuff in class now to, and find those kind of problems so difficult.

Second one, i believe you would go:

using the cylindrical shell method

2pi (integral from 0 to 4 of x(sinx) dx

thats just what i think, i could be off!