Re: question
- To: mathgroup at smc.vnet.net
- Subject: [mg43534] Re: [mg43473] question
- From: Hugh Walker <hwalker at gvtc.com>
- Date: Fri, 19 Sep 2003 03:41:57 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On Thursday, September 18, 2003, at 04:38 AM, Aslaninejad Morteza wrote:
>
> I have solved a differential equation numerically with NDSolve and
> now, I
> would like to do the following step but I don't know how?
> 1- Take the derivative of the answer first.
> 2- Sum the square of answer and the square of the derivative secondly.
> thanks in advance
Hi Aslaninejad;
sol = x/.NDSolve[{x''[t]+0.3 x'[t]+x[t]==0, x[0]==1,x'[0]==0},
x,{t,0,10}]//First;
img1 = Plot[sol[t],{t,0,10}];
img2 = Plot[D[sol[t],t]//Evaluate,{t,0,10}];
img3 = Plot[D[sol[t],{t,2}]//Evaluate,{t,0,10}];
Best wishes,
==========
Hugh Walker
Gnarly Oaks