Hi, I came upon this problem in an old paper in my desk. I remember that I read it on the internet (I'm almost sure from the math blog gaussianos.com) and couldn't solve it. I study engineering. The problem is to find an ƒ(t) such that: ƒ[(x^2) + x*y + ƒ(y)] = [ƒ(x)]^2 + x*ƒ(y) + y I'm not sure if it asked to find a general function that meets this condition or just a particular solution. Anyone knows how to get their hands around it? Thanks!