Iterating NDSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg7117] Iterating NDSolve*From*: darrmis at aol.com (Darrmis)*Date*: Sun, 11 May 1997 02:57:16 -0400 (EDT)*Organization*: AOL http://www.aol.com*Sender*: owner-wri-mathgroup at wolfram.com

Can anyone help? I set up a system of two equations after defining the expressions f and g. NDSolve[{t'[v]==g, t[0]==10000,x'[v]==f, x[0]==0,{t,x},{v,0,20}] The problem is, both f and g also depend on a parameter that I call theta (theta actually represents a chemical concentration, this is a kinetics problem). I can simply vary theta in my definition of f and g and solve the equations several times to see how solution varies with theta. I did this (by rewriting the input for theta and the NDsolve command about 50 times to vary theta from 0 to 50). I can then evaluate x[v] at several values of v for each theta and make a list for each theta and apply the function ListPlot3D. This is very inefficient way to graph x[v,theta]. Is there a simple way to do this in 3 or 4 command lines. I'd like in general to numerically solve ODE's and then plot results as function of two variables. (Is it possible to define a function of the variable theta as the solution to the NDSolve command? When I try to do this I get error message.). Any help would be greatly appreciated.