Re: how can I solve a function Erfc

*To*: mathgroup at smc.vnet.net*Subject*: [mg48442] Re: how can I solve a function Erfc*From*: DrBob <drbob at bigfoot.com>*Date*: Sun, 30 May 2004 06:12:03 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

I've used Solve below, but I had to do a couple of steps manually, first. Erfc[L/(4*(Dg*t)^(1/2))] == 9/10; %[[1,1]] == InverseErfc[Last[%]]; (#1^(-2) & ) /@ %; Solve[%, t]; f[L_, Dg_] = t /. First[%] L^2/(16*Dg*InverseErf[Infinity, -(9/10)]^2) Plot[f[ell, 5*10^5], {ell, -10, 10}]; I wonder why Solve can't deal with the original equation? Bobby From: aude (montgermont.aude at ec-lille.fr) To: mathgroup at smc.vnet.net Subject: [mg48442] how can I solve a function Erfc This is the only article in this thread View: Original Format Hi, I have to solve this function: Erfc[L/(4*(Dg*t)^(1/2))]= 0.9 Dg is constant. Dg=5*10^5 I want to plot t as a function of L. thanks. aude