# [SOLVED] cylindrical coordinates...

• October 11th 2007, 09:32 AM
mugsy777
[SOLVED] cylindrical coordinates...
I don't know why I can't figure this out. How would you write z=x^2-y^2 in cylindrical coordinates? I know that obviously if it were x^2+y^2 you would simply have z=r^2...
• October 11th 2007, 09:41 AM
Jhevon
Quote:

Originally Posted by mugsy777
I don't know why I can't figure this out. How would you write z=x^2-y^2 in cylindrical coordinates? I know that obviously if it were x^2+y^2 you would simply have z=r^2...

recall, for cylindrical coordinates, we use $(x,y,z) = (r \cos \theta , r \sin \theta, z)$

so simply replace x with $r \cos \theta$ and y with $r \sin \theta$ and simplify
• October 11th 2007, 11:12 AM
tukeywilliams
Cylindrical Coordinates are of the following form: $(r, \theta , z)$