In the Mathematica session on the ACS machine taco shown here, I solve the Go-Back-N example (pp.4-5 of the Point to Point/Multidrop Links unit in our printed lecture notes) for the case alpha = 1. I am also showing you a little about how the on-line help works, and the ctrl-c kill feature. Script started on Fri Nov 14 15:56:45 1997 taco 1: /pkg/math/bin/math Mathematica 3.0 for SPARC Copyright 1988-96 Wolfram Research, Inc. -- Terminal graphics initialized -- In[3]:= ?Solve Solve[eqns, vars] attempts to solve an equation or set of equations for the variables vars. Solve[eqns, vars, elims] attempts to solve the equations for vars, eliminating the variables elims. In[5]:= Solve[{pi2 (1-p) + pi1 == pi2, pi1 == pi0, ^C Interrupt> a In[5]:= Solve[{pi2 (1-p) + pi1 == pi2, pi1 == pi0, pi0+pi1+pi2 == 1}, {pi0, pi1, pi2}] p p 1 Out[5]= {{pi0 -> -------, pi1 -> -------, pi2 -> -(--------)}} 1 + 2 p 1 + 2 p -1 - 2 p In[6]:= Quit taco 2: e exit script done on Fri Nov 14 16:15:48 1997 script done on Fri Nov 14 16:15:48 1997