Re: Recursion Limit & Symbolic Differentiation

*To*: mathgroup at smc.vnet.net*Subject*: [mg52265] Re: [mg52258] Recursion Limit & Symbolic Differentiation*From*: yehuda ben-shimol <benshimo at bgu.ac.il>*Date*: Sat, 20 Nov 2004 03:41:33 -0500 (EST)*References*: <200411180644.BAA10625@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Since you did not send the function and how you try to differentiate it I'm submitting a basic response Say your function is defined as f[x_,y_,z_]:=Sin[x y z]; Use Dt for total derivative Dt[f[x, y, z]] and get Cos[x y z] (y z Dt[x] + x z Dt[y] + x y Dt[z]) This assumes that x, y and z may be functions of other variables For partial derivatives use D[ ], for example differentiate the given Sin[x y z] according to x D[f[x, y, z], x] and get y z Cos[x y z] I know this is VERY basic but I hope this helps yehuda Erin wrote: >Hi, > >I'm new to Mathemtica and I'm trying to differentiate a multi-variable >function >f(x,y,z). When doing so I get a recusion limit 256 reached message. > >When examining my equations, I don't see recursion in the expressions. >It should be simple substitution of one expression into the other. >(Its just easier for me to write it that way). > >How do I know if this is a valid message, and how do I know if my >expressions will actually be solved / simplified by Mathematica if I >increase the recursion limit? > >I have 2GB RAM and Mathematica fills it, then the Kernel runs out of >memory and stops trying to solve the problem. > >Thanks. > > >

**References**:**Recursion Limit & Symbolic Differentiation***From:*erinbaily@mac.com (Erin)