1. The problem statement, all variables and given/known data I am given the following problem: [URL]http://forum.allaboutcircuits.com/attachment.php?attachmentid=35938&d=1320027350[/URL] 2. Relevant equations 3. The attempt at a solution My known equations and attempt to the problem: [URL]http://forum.allaboutcircuits.com/attachment.php?attachmentid=35940&stc=1&d=1320028178[/URL] Basically, my answer to the problem is not the same as the book's answer, and I'm pretty sure I'm using the right equations. What could I possibly be doing wrong here? I've been trying to figure this out for three hours now, and am now frustrated. I apologize for my ignorance here, but any advice or tips will be greatly appreciated.