"Use calculus techniques to show that the graph of the quadratic function f(x) = ax^2 + bx + c, a > 0, is decreasing on the interval x < (-b/2a) and increasing on the interval x > (-b/2a)."
I have no idea where to start really. Can someone lead me in the right direction?
Thanks!
I know what you're talking about, but I don't know how to represent it on paper. How do I show that it is increasing on the one interval, but decreasing on the other interval?
(I know that the quadratic function looks like a parabola and I can think about how at the zero slope point it would change from decreasing to increasing, but I can't represent it)