1. The problem statement, all variables and given/known data Given the equation dy/dx = y^4 - x^4, y(0) = 7, determine whether the existance/uniqueness theorem implies that the given initial value problem has a unique solution. 2. Relevant equations Existence/Uniqueness Theorem 3. The attempt at a solution To my understanding, you must assign f(x,y) = y^4 - x^4 then derive f(x,y) in terms of y. f'(x,y) = 4y^3 This is as far as I have gotten.