In: Math
| f(r,?) | f(x,y) | 
| r(cos(?)) | = x | 
| r(cos(2?)) | = ? | 
| r(cos(3?)) | = x3-3xy2/x2+y2 | 
| r(cos(4?)) | = ? | 
| r(cos(5?)) | = ? | 
Please complete this table. I am having trouble converting functions from polar to cartesian in the three dimensional plane.
I understand that x=rcos(?) and y=rsin(?) and r2 = x2 + y2 , but I am having trouble understanding how to apply these functions.