Derivative and Second Derivative test

Question

Hi, I'm stuck on this problem, could someone please walk me through it.

⦁ Identify all absolute and relative extrema of the function using the Second Derivative Test. Justify your work algebraically.

f(z) = 2z⁴ -16z³+20z²-7

Find critical points w/ the first derivative:

Apply the Second Derivative Test to find maximums/ minimums:

Answer 1

The first step is to take the first derivative using the Power Rule. Have you done that?