       Re: Stupid simple question about counting derivatives

• To: mathgroup at smc.vnet.net
• Subject: [mg33466] Re: [mg33437] Stupid simple question about counting derivatives
• From: Tomas Garza <tgarza01 at prodigy.net.mx>
• Date: Fri, 22 Mar 2002 04:06:44 -0500 (EST)
• References: <200203211427.JAA18170@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Are you sure you're leaving a space between the a and the x in a x? If you
aren't, then ax is a symbol, an unknown symbol, and that is why you're

In:=
D[ax, x]
Out=
0

In:=
D[a*x, x]
Out=
a

In:=
Dt[ax, x]
Out=
Dt[ax, x]

In:=
Dt[a*x, x]
Out=
a + x*Dt[a, x]

Tomas Garza
Mexico City
----- Original Message -----
From: "Jack" <kielczew at poczta.onet.pl>
To: mathgroup at smc.vnet.net
Subject: [mg33466] [mg33437] Stupid simple question about counting derivatives

> How do I get Mathematica 2.2 to count the derivatives of the simplest
> parametric functions, i.e.
>
> (ax)', where a is the parameter and x is the variable. I want to get:
>
> a
>
> (Hey, I said it was stupid).
>
> D[ax,x] gets me 0, Dt[ax,x] gets me Dt[ax,x] and I haven't figured out
> how to use Constants and NonConstants. I'd be grateful for any help as
> this simple problem is driving me crazy.
>
>
> --
> Jacek Kie³czewski
> kielczew at poczta.onet.pl
>
>
>
>
>

```

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