1. The problem statement, all variables and given/known data Obtain intervals x∈[0,α] for the existence of a unique solution dy/dx = f(x,y) = e^-(y-x)^2; y(0) = 0 on the rectangle B = [0,a]x[-b,b] 2. Relevant equations 3. The attempt at a solution Since both dy/dx and it's partial derivative of y are both continuous, a unique solution exists. Thus an interval for existence for t is [0,t*], where t* = b/(max|f(x,y)|). I'm not sure how to determine max|f(x,y)|. Any help is appreciated.