f(x) = 4x ^ 5 - 8e ^ x , find:

So,
Given:
We're first asked to find the deritative of the function. This is:
Now, to find f ' (3) what we do is to replace x by 3 in the expression of the deritative:
To find f '' (x), what we do is to take the deritative of the first deritative:
And, to find the value of f ' ' (3), what we do is to replace x by 3 in the expression above: