Let f be differentiable at x=3. Which equation expresses that the average rate of change of f on the interval [3,3+h] equals the instantaneous rate of change at x=3?
a) hf(3+h)−f(3)=f′(3+h)
b) hf(3+h)−f(3)=f(3)
c) hf(3+h)−f(3)=f′(3)
d) hf(3+h)−f(3)=2f(3)+f(3+h)