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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