Question

Find the points on the curve given below, where the tangent is horizontal. (Round the answers to three decimal places.)
y = 8 x ^3 + 2 x ^2 - 2 x + 3

Answer 1

dy/dx=0

Answer 2

0=24x^2+4x-2.......12x^2+2x-1......\[x=\frac{-2+/-\sqrt{4-4(12(-1)}}{2}\]

Answer 3

x=-4.640 and 2.640

Answer 4

The two requested points are:
{{-0.384, 3.61}, {0.217, 2.742}}

Refer to the attached Mathamatica solution.