Re: Chain rule

*To*: mathgroup at smc.vnet.net*Subject*: [mg24578] Re: Chain rule*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Tue, 25 Jul 2000 00:56:10 -0400 (EDT)*Organization*: Universitaet Leipzig*References*: <8lgu0g$2ip@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi, Dt[2*t^2 - 1]/Dt[2t + 5] ? Regards Jens Claude wrote: > > Hello, > > I am just trying to solve: > dy/dx when x = 2t + 5 and y = 2t^2 - 1. > > Can it be done directly by Mathematica or do I have to solve dy/dt and > dx/dt and finally divide dy/dt by dx/dt? > > I tried posing x = 2t + 5 and y = 2t^2 - 1 and ask solve for D [y,x], but > that does not evaluate properly (the answer is 2t). I would have thought > that Mathematica would have used the chain rule automatically. > > Thanks for your help,