How to find the maximum and minimum when given derivative?
Can someone please explain where I went wrong with 4g? I got max at -3 and min at 4 by drawing the sign graph, but the answer says the exact opposite.
Thanks!
Can someone please explain where I went wrong with 4g? I got max at -3 and min at 4 by drawing the sign graph, but the answer says the exact opposite.
Thanks!
1 Answer
Oct 3, 2017
We start by finding critical numbers:
0 = -x^2 + x + 12
0 = x^2 - x - 12
0 = (x - 4)(x + 3)
x = 4 or -3
So you are correct about the two turning points.
If we select a test point between the two turning points, say
y' = 0^2 + 0 + 12 = 12
Since this is positive we know that the function is increasing on
Hopefully this helps!