41. dy dx dy dx dy dx d²y dx² d²y dx² d²y dx² d³y dx³ = 0 = 0 = 0 = 0 < 0 > 0 ≠ 0 At point P Remember to physically do and say each step in a question including saying if a certain point is a max., min. or point of inflection. Maximum point Minimum point and (doesn’t change sign on either said of P) Point of inflection