Drawing curves in Spherical coordinate

[athrun200]

I had a tutorial today and my tutor said these questions are very trivial so we can simply look at it at home.

But after going home, I found that I don't know how to do Q 35.
I know that p<3 is responsible for the big sphere with r=3. But I don't know why the other part is responsible for the small sphere

 

[tiny-tim]

hi athrun200!

hint: draw a circle with B at the bottom, centre O, and any point P

then BP = 2OBcosOBP