RE: Entering constant placeholders

*To*: mathgroup at smc.vnet.net*Subject*: [mg32356] RE: [mg32328] Entering constant placeholders*From*: "Florian Jaccard" <jaccardf at eicn.ch>*Date*: Wed, 16 Jan 2002 03:30:09 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

You dont have to tell that a, b and c are constants. It is the case ! In[9]:= D[a*x^3+b*x^2+c*x+d,x] gives the correct answer. If you want that a,b,c and d are functions of x, you have to write : D[a[x]*x^3 + b[x]*x^2 + c[x]*x + d[x], x] It may be that you have forgotten to put a space between a and x ! If you write "ax" , Mathematica doesn't know that you meen "a*x" ! Meilleures salutations Florian Jaccard EICN-HES e-mail : jaccardf at eicn.ch -----Message d'origine----- De : progman [mailto:dglfl at home.com] Envoyé : mar., 15. janvier 2002 08:30 À : mathgroup at smc.vnet.net Objet : [mg32328] Entering constant placeholders I can't seem to make this work. When I enter the following, I get these errors: SetAttributes[a,b,c, Constant] Syntax::tsntxi: "SetAttributes a,constant" is incomplete; more input is needed. d(ax^3 + bx^2 + cx + d)/dx The answer should be 3ax^2+2bx+c . I can't figure out how to tell mathematica that a,b, & c are constants. Thanks