Re: To plot solutions, FindRoot as a function

*To*: mathgroup at smc.vnet.net*Subject*: [mg37380] Re: [mg37341] To plot solutions, FindRoot as a function*From*: Tomas Garza <tgarza01 at prodigy.net.mx>*Date*: Fri, 25 Oct 2002 02:48:44 -0400 (EDT)*References*: <200210240655.CAA05094@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Well, yes, perhaps a bit too naive. Bear in mind that 1) a 3D plot needs Plot3D; 2) The result of FindRoot is in the form of a rule wherefrom you have to extract the actual value you need. Try this: In[1]:= sol[a_, b_] := FindRoot[a*Tanh[b*x] == x, {x, {0.01, 0.1}}] In[2]:= Plot3D[sol[a, b][[1,2]], {a, 1, 2}, {b, 1, 2}]; Tomas Garza Mexico City ----- Original Message ----- From: "Veniamin Abalmassov" <V.Abalmassov at unibas.ch> To: mathgroup at smc.vnet.net Subject: [mg37380] [mg37341] To plot solutions, FindRoot as a function > Hello, > > I'd like to plot the solution of an equation which depends on two > parameters, e.g. > > a*Tanh[b*x] == x > > So, I'd like to see it in 3D, one axis is "a", other is "b", and the last > is "solution". > > I've tried naively to do it as follows: > > sol[a_,b_]:=FindRoot[a*Tanh[b*x] == x, {x, {0.01, 0.1}}] > Plot[sol[a,b], {a, 1, 2}, {b, 1, 2}] > > And it doesn't work. Help me, please. What can I do? > > Thanks a lot, > > Veniamin > > > >

**References**:**To plot solutions, FindRoot as a function***From:*Veniamin Abalmassov <V.Abalmassov@unibas.ch>