dsolve?

*To*: mathgroup at smc.vnet.net*Subject*: [mg57001] dsolve?*From*: Chris Chiasson <chris.chiasson at gmail.com>*Date*: Thu, 12 May 2005 02:32:49 -0400 (EDT)*Reply-to*: Chris Chiasson <chris.chiasson at gmail.com>*Sender*: owner-wri-mathgroup at wolfram.com

Dear Mathematica Gurus: In trying to find the area under a curve for polytropic compression of an ideal gas, I have run into a problem with DSolve. I have two workarounds, which are listed below, but I want to use DSolve. Any suggestions? Problem Code: DSolve[{Derivative[1][W][V]==(P1*V1^k)/V^k,W[V1]==0},W,V] "For some branches of the general solution, the given boundary conditions lead \ to an empty solution." Workaround 1: Assuming[{V1>V2>0},Integrate[(P1*V1^k)/V^k,{V,V1,V2}]] Workaround 2: First[DSolve[{Derivative[1][W][V]==(P1*V1^k)/V^k},W,V]] First[Solve[W[V1]==0/.%,C[1]]] FullSimplify[W[V]/.%%/.%] Thank you for your valuable time, -- Chris Chiasson http://chrischiasson.com/ 1 (810) 265-3161