Re: Deriviation d/dt(x(t))
- To: mathgroup at smc.vnet.net
- Subject: [mg27437] Re: Deriviation d/dt(x(t))
- From: Hendrik van Hees <h.vanhees at gsi.de>
- Date: Sun, 25 Feb 2001 20:55:41 -0500 (EST)
- References: <97a6up$akb@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
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? Mathematica 4.0 for Students: Linux Version Copyright 1988-1999 Wolfram Research, Inc. -- Motif graphics initialized -- In[1]:= rSqr=x^2+y^2; In[2]:= Dt[rSqr,t] Out[2]= 2 x Dt[x, t] + 2 y Dt[y, t] Hope that helps ;-). -- Hendrik van Hees Phone: ++49 6159 71-2751 c/o GSI-Darmstadt SB3 3.183 Fax: ++49 6159 71-2990 Planckstr. 1 mailto:h.vanhees at gsi.de D-64291 Darmstadt http://theory.gsi.de/~vanhees/index.html