1. The problem statement, all variables and given/known data Find the critical numbers of the function y=√(1-x^2) 3. The attempt at a solution y'=-x/√(1-x^2 )=0 -x/√(1-x^2 )=0 Here, I stuck. If I continue with this equation, my answers are x1=0 and x2 is less than 1. But if I try to get rid of the root in order to find the critical points by doubling the both sides of equation, my answer is x1=0, x2 not equal to 1. These are quite different answers. Please help me out with the problem.