Are some equations unsolvable?

*To*: mathgroup at smc.vnet.net*Subject*: [mg128061] Are some equations unsolvable?*From*: Sergio Sergio <zerge69 at gmail.com>*Date*: Wed, 12 Sep 2012 03:00:44 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net

Hi, This is what I have: f = (1/(sigma*Sqrt[2 Pi]))*Sqrt[(Pi/(-1/(2*sigma^2)))]* Exp[((m/sigma^2)^2)/4*(-1/2*sigma^2) + (m^2/(2*sigma^2))] Solve[f == 216, sigma] And I get this message: "This system cannot be solved with the methods available to Solve" Is it because there is no way to isolate sigma? Or am I doing something wrong? Thanks

**Follow-Ups**:**Re: Are some equations unsolvable?***From:*Bob Hanlon <hanlonr357@gmail.com>