Re: Related rates

*To*: mathgroup at smc.vnet.net*Subject*: [mg45770] Re: [mg45759] Related rates*From*: "Sseziwa Mukasa,,(978) 536-2359" <mukasa at jeol.com>*Date*: Sat, 24 Jan 2004 00:36:21 -0500 (EST)*References*: <200401230815.DAA27745@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On Jan 23, 2004, at 3:15 AM, DIAMOND Mark R. wrote: > Just to put a bit of meat into this but keeping it much simpler that > the > problem I really want, consider an oBject (B) approaching a bullseye > that > has one ring at a distance R from the centre (C) of the bulls-eye. > Distance > from target at time t is z[t]. Angle theta is angle RBC. How can I > calculate > d-theta/dt. Assuming you have defined theta and z then: D[theta[z[t]],t] > But > what is the appropriate way to set up such a problem in Mathematica? Define theta[z] and z[t], then take the derivative of theta[z[t]] with respect to t. > Do I need to create a dummy function for the velocity, or can I > specify the > relationships between theta and z, and between velocity and z and go > from > there. If you already know D[z[t],t] then you can simply write D[theta[z],z] D[z[t],t] as well. Regards, Ssezi

**References**:**Related rates***From:*"DIAMOND Mark R." <dot@dot.dot>