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Re: Deriviation d/dt(x(t))

• To: mathgroup at smc.vnet.net
• Subject: [mg27438] Re: [mg27407] Deriviation d/dt(x(t))
• From: Reza Malek-Madani <research at usna.edu>
• Date: Sun, 25 Feb 2001 20:55:42 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

Hi Chrsitian:  I think you want to try something like

D[x[t]^2+y[t]^2==r^2,t]


Reza.

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Reza Malek-Madani               Director of Research
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On Sun, 25 Feb 2001, Christian Maier wrote:

> I have a problem, having a definition of a circle: x^2+y^2=r^2
> Where x and y are functions of the time:  x(t), y(t) and r ist a constant.
> 
> Now I want to deriviate the equation to get the velocity vector.
> It should be : 2 x dx/dt +2 y dy/dt = 0
> 
> Can anyone tell me how to do?
> Thans in advance!
> 
> Christian Maier
> 
> 
> 
> 
>