(i) The derivative is the gradient of the tangent to a graph; the derivative is the rate of change of with respect to .
(ii) The interest rate is the rate of change of value of a dollar loan with respect to time.
(iii) Speed is the rate of change of position with respect to time; acceleration is the rate of change of speed with respect to time.
(iv) Power is the rate of change of energy with respect to time.