Re: Solve question

*To*: mathgroup at smc.vnet.net*Subject*: [mg57470] Re: [mg57457] Solve question*From*: "David Park" <djmp at earthlink.net>*Date*: Sun, 29 May 2005 01:03:28 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

L.W., Here is an example. eqn = a x + b == c; xsol = Solve[eqn, x] {{x -> (-b + c)/a}} Notice that Mathematica returned a List within a List. That is because there may be more than one solution, and for multiple equations there may be more than one variable in each solution. Generally we will want to extract a specific solution by taking a specific part of xsol. Let's create an x function that depends on the a,b,c parameters. We do that by using Replace denoted by "/.". We want only the solution in the inner bracket so we use the following: x[a_, b_, c_] = x /. Part[xsol, 1] (-b + c)/a which we can now use. x[p, q, 3] (3 - q)/p David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: Sterritt, Lanny [mailto:lanny.sterritt at lmco.com] To: mathgroup at smc.vnet.net When the Solve command is used to obtain the value of a variable in an equation, something like {x -> value} is returned. How does one get Mathematica to automatically apply this value to following expressions in a notebook? L.W.Sterritt