Rate (mathematics) - Rate of Change

Rate of Change

A rate of change can be formally defined in two ways:

\begin{align}\mbox{Average rate of change}&=\frac{f(a+h)-f(a)}{h}\\
\mbox{Instantaneous rate of change}&=\lim_{h \to 0}\frac{f(a+h)-f(a)}{h}\end{align}

where f(x) is the function with respect to x over the interval from a to a+h. An instantaneous rate of change is equivalent to a derivative.

An example to contrast the differences between the average and instantaneous definitions: the speed of a car can be calculated:

  1. An average rate can be calculated using the total distance travelled between a and b, divided by the travel time
  2. An instantaneous rate can be determined by viewing a speedometer.

Read more about this topic:  Rate (mathematics)

Famous quotes containing the words rate of, rate and/or change:

    At this very moment,... the most frightful horrors are taking place in every corner of the world. People are being crushed, slashed, disembowelled, mangled; their dead bodies rot and their eyes decay with the rest. Screams of pain and fear go pulsing through the air at the rate of eleven hundred feet per second. After travelling for three seconds they are perfectly inaudible. These are distressing facts; but do we enjoy life any the less because of them? Most certainly we do not.
    Aldous Huxley (1894–1963)

    All of us failed to match our dreams of perfection. So I rate us on the basis of our splendid failure to do the impossible.
    William Faulkner (1897–1962)

    Ever since surgery began, man’s destiny has been to suffer, in order that he might be cured. And no one can change that, gentlemen.
    Jean Scott Rogers, and Robert Day. Mr. Blount (Frank Pettingell)