Hello, and thank you for your time!
I can´t seem to find the way to simplify the result of this vector´s norm. I need to find the final value of it.
Any idea to do it simpler?

Hello my Maple friends! :)
I was wondering if there is any command in Maple that can help me find the equation of a surface from it´s parametric form and the other way around, a parametric form from a surface equation!
For example, if
x :=(s, t) -> s cos(t)
y :=(s, t) -> s sin(t)
z :=(s, t) -> s^2

then S: x^2+y^2=z

Thank you for your help.
English is not my mother tongue; please excuse any errors on my part.

Hi! I can´t see what i´m doing wrong! :( Thank you for your help!!!

Hi! my name is Euge, i live in Argentina!
I´m solving a problem that ask me to find an ODE from a family of curves, 
I know this is pretty simple, I have to derive the equation two times, but i can´t find a comand in maple that helps me do that. Is there any?
Thank you!