Hello I'm really stuck on a question and could do with some help. 1. The problem statement, all variables and given/known data http://img268.imageshack.us/img268/2161/19947313.jpg [Broken] 2. Relevant equations http://img139.imageshack.us/img139/3478/24591171.jpg [Broken] 3. The attempt at a solution http://img187.imageshack.us/img187/2808/54885491.jpg [Broken] I'm so confused. I'm going round and round in circles. I've proven that 256 does indeed equal 256, and 1280, funnily enough, equals 1280. I've tried applying the Product Rule at various stages to no avail. I just can't see how to get a numeric value of a or b. The only thing like this that we've done in class was a question where we were given an amount of fencing and had to work out the maximum quadrilateral area that it could enclose. But I'm ending up with products equalling 0 instead of a number and a letter being added and don't know what to do. I'd appreciate any and all help/hints/tips. Thanks.