Calculating with value instead of symbol

*To*: mathgroup at smc.vnet.net*Subject*: [mg2878] Calculating with value instead of symbol*From*: Andreas Groehn <agroehn at email.uni-kiel.de>*Date*: Thu, 4 Jan 1996 03:04:36 -0500*Organization*: Institut fuer Weltwirtschaft

I need to calculate the following sequence: W=x^2 Y[x_]:=x W If I differentiate Y[x] in respect to x, I get different solutions, depending on the employed function, Y'[x] or D[Y[x], x], because Y is defined as Y[x]=x W and not as Y[x]= x^3. How can I get Mathematica to work with the value of W to receive the Y[x]= x^3? Thank you very much for your help, Andreas Groehn ==== [MESSAGE SEPARATOR] ====