If you were given a graph of a function instead of its equation, explain how to find the average rate of change between two points. How does this differ from finding the instantaneous rate of change? Please use a diagram to help you explain.

Answer 1

it is the slope of the line joining the points. Recall that on the interval [a,b] that is

((f(b) - f(a)) / (b-a)

I'm sure your calculus text has illustrations and explanations.
I know google does.