Answer:
True
Explanation:
The first derivative tells you the slope of the graph at a specific point. If f'(c) =0, then that means that at f(c), the slope of the graph is 0. It is neither going up nor down
The second derivative tells you the slope of the slope of the graph. If f''(c) < 0, this means that the slope is decreasing. This means that going from the left to f(c), the slope is greater than the slope at f(c), and going from f(c) to the right, the slope is less than the slope at f(c).
Therefore, since the slope at f(c) is 0, the slope is positive to the left of f(c) and negative to the right of f(c). This means that the graph is going up until it hits f(c) and then goes down. Because f(c) is greater than the values to the left of it (because it is going up until it hits f(c)) and the values to the right of it (because it is going down past f(c)), f(c) is a local maximum