Without using a calculator, find the values of x for which the graph of y=x^3 - 6x^2 is concave downward.
It's pretty straight-foward.
Exactly where is your difficulty?
Find the values of x for which the graph of is concave downward.
First derivative: .
Second Derivative: .
The graph is concave down when the second derivative is negative.
So we have: .
The graph is concave down for