1. The problem statement, all variables and given/known data Find d2y/dx2 in terms of x and y for the following equation: xy + y^2 = 1 COMPLETELY SIMPLIFY 2. Relevant equations dy/dx 3. The attempt at a solution so i get -y/(x+2y) for the dy/dx. When I try to find the 2nd derivative and plug in dy/dx, I get 2y(x+y)/(x+2y)^3.....the sheet says the correct answer is 2/(x+2y)^3. I don't understand I've done this problem 3 times and still don't get that answer!