Question

Help!? I don't understand how to figure this out.

Answer 1

Question (a):

We're asked to write (in interval notation) where the function is decreasing.

We can see that the function decreases from `x = -4` to `x = 2` (because it is increasing on either side of this region). Thus, in interval notation this is

`(-4,2)`

Question (b):

`f'(-3.9)` will be negative, because it occurs after the local maximum at `x = -4` (the function is decreasing during this interval, so its derivative is negative)

`f'(-4.1)` will be positive, because it is located before the local maximum (the function is increasing during this interval, so its derivative is positive)