1. The problem statement, all variables and given/known data (16x)/(x^2+4) for -5 (less than OR equal to) x (less than OR equal to) 5 2. Relevant equations Set the derivative of the equation equal to 0, solve for x to find the critical points, then plug and check for validity. 3. The attempt at a solution I used product rule for (16x)*(x^2+4)^-1 I got the derivative as (-32x^2)/((x^2+4)^2) + (16/(x^2+4)) which I then set equal to 0. I then made an attempt to solve for x, but got x^2(48x^2+256)=-256, which I'm very unsure of, and am also not sure how to solve. Help is appreciated.