Re: Creating a function that is a derivative of another function??
- To: mathgroup at smc.vnet.net
- Subject: [mg86743] Re: Creating a function that is a derivative of another function??
- From: Bhuvanesh <lalu_bhatt at yahoo.com>
- Date: Thu, 20 Mar 2008 02:52:15 -0500 (EST)
In your case, dW is trying to compute (more or less) D[a*t + b*t^2 + c*t^3 /. t->0, t /. t->0] == D[0, 0], which naturally gives an error message, since zero is not a valid variable. Here's one way to do what you want: In:= W[t_] := a*t + b*t^2 + c*t^3 In:= dW[t0_] := Derivative[W][t0] In:= dW[t] //InputForm Out//InputForm= a + 2*b*t + 3*c*t^2 In:= dW Out= a Bhuvanesh, Wolfram Research