1. The problem statement, all variables and given/known data Differential equation: 2xyy' = x^2 + y^2 Relation: y^2 = x^2 - cx 2. Relevant equations 3. The attempt at a solution Hello, I can normally solve this problems with ease; however, I am having trouble with this particular problem. I have performed the implicit differentiation to get: (2yy' = 2x - c). However, I can't seem to figure out where to go from here. I am thinking that perhaps there is some obvious simplification that I am missing. If somebody can point me in the right direction I'd greatly appreciate it. Thanks.