4. Let f(x) and g(x) be the differentiable functions graphed here. At x=c, the vertical distance between these curves is the greatest. Is there anything special about the tangents to the two curves at x=c? Give reasons for your answers. f(x) is the line that is concave up, and g(x) is the line that is concave down.

I am in the first semester of calculus, so this would have to apply to that.... but I have no clue where to start on this one :P. So help would be nice.