Hi, I was provided a http://eng-tips.com/viewthread.cfm?qid=372664# [Broken] that I'm lost on. I was given an equation that we solved for earlier in the semester using the finite difference (dx method). (first image below). The http://eng-tips.com/viewthread.cfm?qid=372664# [Broken] wasn't clear when assigning homework, and says he wants us to double check this equation to make sure it's "self consistent" using the energy method. I approached the professor with additional questions but he kept repeating himself, that he wants us to cross-check the solution. He said we used a "local" method to solve for this solution, and he wants us to use a "global" method to double check the solution. I have tried using electrical analogies with thermal resistance to resolve the solution, but can't seem to get it right. The first image is the equation, the second image is the setup we used initially to derive the solution. http://imgur.com/HaXiH8A http://imgur.com/K3FXMlM Does anyone know how I should go about symbolically double checking this http://eng-tips.com/viewthread.cfm?qid=372664# [Broken]? Thanks in advance!