from part (b) and solve for the x-values when f′′(x) = 24x^2 + 12 = 0. So, x = and x = −
. To determine the y-coordinates for these points of inflection, determine f(x) at each of
these points: f = and f = . So the points of inflection occur at
and .
- Consider the curve given by x^3 y^2 − 5x + y = 3.
(a) Find .
Use implicit differentiation: 2x^3 y + 3x^2 y^2 − 5 + = 0. Simplify and isolate : =
.
(b) Find .
Use the derivative from part (a) and differentiate again using implicit differentiation: =
. Replace the value for from part (a) for the final
solution:
No need to simplify.
(c) Find the equation of the normal lines at each of the two points on the curve whose x-
coordinate is −1.
From the original equation, at x = −1, y = −2 or y = 1. Plug those values into from part (a)