Derivatives D[ ] as Functions inside Tables; Need Help!

*To*: mathgroup at smc.vnet.net*Subject*: [mg13102] Derivatives D[ ] as Functions inside Tables; Need Help!*From*: siegman at ee.stanford.edu (AES)*Date*: Tue, 7 Jul 1998 03:44:07 -0400*Organization*: Stanford University*Sender*: owner-wri-mathgroup at wolfram.com

I'm trying to define a function f1[a,x] and its derivative f2[a,x], where from my point of view x is the independent variable and "a" is a parameter I'll change on different runs. So I write, as a simple example: Remove["Global`*"] f1[a_,x_] :=a Cos[x] + a^2 Sin[x] f1[a,x] f2[a_,x_] := D[f1[a,x],x] f2[a,x] a=2 f1[a,x] f2[a,x] Table[{x, f1[a,x], f2[a.x]} // N, {x,0,4}] // TableForm and everything looks fine -- except the function f2[a,x] will not evaluate inside the Table[ ]. I don't understand this -- help in understanding will be much appreciated. siegman at ee.stanford.edu