Re: Using Solve[] - What did I do wrong?

*To*: mathgroup at smc.vnet.net*Subject*: [mg109321] Re: Using Solve[] - What did I do wrong?*From*: dh <dh at metrohm.com>*Date*: Wed, 21 Apr 2010 07:48:15 -0400 (EDT)*References*: <hqmd3t$pti$1@smc.vnet.net>

On 21.04.2010 10:30, eric948470 wrote: > Hi, > > If you look at the command below, you would probably be able to > understand what I was trying to do. I have linear equations, and I > want to solve for the variable g2, and I don't want the variables dx1, > dx2, dy1 and dy2 in the answer. What I get for the output is {{}}. > What did I do wrong? > > Solve[{phi2 + a2*dx1 + b2*dy1 + c2*dx2 + d2*dy2 == 0, > psi2 + A2*dx1 + B2*dy1 + c2*dx2 + D2*dy2 == 0, dx2 == -g2 - f2*dy2, > dx1 == -g1 - f1*dy1}, g2, {dx1, dx2, dy1, dy2}] > Hi, every elimination of a variable "eats up" one equation. Therefore, you need 5 equations to eliminate 4 variables and solve for g2. cheers, Daniel -- Daniel Huber Metrohm Ltd. Oberdorfstr. 68 CH-9100 Herisau Tel. +41 71 353 8585, Fax +41 71 353 8907 E-Mail:<mailto:dh at metrohm.com> Internet:<http://www.metrohm.com>