Interesting problem about latitude!

[Guest]

For a planet of radius a, find the area of the surface between the equator and latitude
60 degrees north.

I think this is an interesting problem. I looked over instructor's examples and wanted to see if anyone else can find a different way... He somehow used a series? :shock:

 

[tkhunny]

Several ways to go about that one.

This one was interesting: http://mathforum.org/library/drmath/view/54831.html