infinity problem in mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg74103] infinity problem in mathematica*From*: traz <t_raz at yahoo.com>*Date*: Sat, 10 Mar 2007 06:51:13 -0500 (EST)

I'm trying to solve a system of equations in the form of a large matrix product in mathematica. The problem is Mathematica keeps running and never reaches a solution. One way to figure out the problem in my matrix is by setting certain symbols to infinity and zero so I can see if the solution reduces to an answer that I expect. So how can I set certain symbols to be infinitely large and solve the system. I have a much simpler example below: Solution = Solve[{{{-k1, k2 + k3}, {k1, -k2 - k3}}.{{x}, {y}} == 0, x + y == 1}, {x, y}][[1]] rate = k3 * y /. Solution I can always try to find the limit when k1 goes to infinity and k2 goes to zero so the rate solution reduces to k3, but I am not getting a solution for the matrix product (one that is much bigger and different from the example here). Trying to set k1 to infinity inside the matrix will not give me a solution. I hope someone can help.