Science:Math Exam Resources/Courses/MATH110/April 2017/Question 06 (b)/Hint 1

The function f has an inflection point at x if f is differentiable at x and if the sign of $f''(x)$ changes at x. Take a look at the places where the sign of $f''(x)$ changes and exclude the points x=-2 and x=2, because f(x) is not differentiable at those points.