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:

    We all run on two clocks. One is the outside clock, which ticks away our decades and brings us ceaselessly to the dry season. The other is the inside clock, where you are your own timekeeper and determine your own chronology, your own internal weather and your own rate of living. Sometimes the inner clock runs itself out long before the outer one, and you see a dead man going through the motions of living.
    Max Lerner (b. 1902)

    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)

    Like dreaming, reading performs the prodigious task of carrying us off to other worlds. But reading is not dreaming because books, unlike dreams, are subject to our will: they envelop us in alternative realities only because we give them explicit permission to do so. Books are the dreams we would most like to have, and, like dreams, they have the power to change consciousness, turning sadness to laughter and anxious introspection to the relaxed contemplation of some other time and place.
    Victor Null, South African educator, psychologist. Lost in a Book: The Psychology of Reading for Pleasure, introduction, Yale University Press (1988)