1. The problem statement, all variables and given/known data f(x) = (x3 - 1)/(x3 + 1) 2. Relevant equations (d/dx)[f(x)/g(x)] = [f`(x)⋅g(x) - f(x)⋅g`(x)]/[g(x)]2 3. The attempt at a solution f`(x) = [3x2(x3 + 1) - 3x2(x3 - 1)]/[(x3 + 1)]2 f`(x) = 3x2[(x3 + 1) - (x3 - 1)]/[(x3 + 1)]2 f`(x) = 3x2(2)/[(x3 + 1)]2 f`(x) = 6x2/(x3 + 1)2 When I made a sign chart for this derivative, I couldn't find any x that could make the value of f`(x) negative. It's always positive, because both terms are squared. So I can't find any interval of decrease, and in turn, any local minimum or maximum. I'm asked to also write the intervals of concave up/down and any inflection points. I highly doubt my professor would assign a problem where I would just write N/A for six of these values. Am I doing something wrong? What x would make this derivative negative? Or perhaps, am I not deriving this correctly?