Re: problems plotting a derivative
- To: mathgroup at smc.vnet.net
- Subject: [mg54550] Re: problems plotting a derivative
- From: Bill Rowe <readnewsciv at earthlink.net>
- Date: Tue, 22 Feb 2005 04:25:41 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
On 2/21/05 at 3:44 AM, rob at pi-overe.com (J. K. Smith) wrote:
>I've tried a lot of ways but nothing has worked so far. The
>following statements are my problem simplified:
>f[x_] := 2x^3;
>ParametricPlot[{D[f[x], x], x^2}, {x, 0, 1}]
>When I run this I get error messages griping about numbers not
>being valid variables but it doesn't end up plotting anything. In
>this example I should see a straight line.
When this happens, it is almost always a result of the way the plot routines evaluate arguements and is resolved by forceing evaluation of the expression before the plot routine gets it.
>I've tried using Evaluate[ D[f[x],x] ]
This is close to what is needed. Try
ParametricPlot[Evaluate@{D[f[x], x], x^2}, {x, 0, 1}]
--
To reply via email subtract one hundred and four