Plotting numerical derivatives

*To*: mathgroup at smc.vnet.net*Subject*: [mg53883] Plotting numerical derivatives*From*: "plizak" <plizak at gmail.com>*Date*: Tue, 1 Feb 2005 04:08:48 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

I'm trying to differentiate a function of the form FTD[t1_, t2_] := a function of t1 and t2 I can get the derivative fine by using: ND[ND[Fun[t1, t2 ], {t1, 1}, 200000], {t2, 1}, 200000 ] However, I'd like to plot it in a 3D plot, and it just doesn't want to work. I get a flat plot with value 0. The code I tried to use is: Plot3D[ND[ND[Fun[t1, t2 ] , {t1, 1}, a] , {t2, 1}, b ], {a, 1, 500000}, {b, 1, 500000}] Any tips on getting this to plot would be greatly appreciated! I don't want to have to code up a way to build a big table and calculate all the cells individually, as I will have to do this for many other functions. If I do have to build a table, is there a quick way to do that in Mathematica? or wouldusing Table[...] be best?