- instantaneous rate of change
An escalator can never break, it can only become stairs. You would never see an “Escalator Temporarily Out Of Order” sign, just “Escalator Temporarily Stairs”. Sorry for the convenience. We apologize for the fact that you can still get up there.
Mitch Hedberg, Just for Laughs, 1998
- Derivative (Wikipedia)
In mathematics, the derivative shows the sensitivity of change of a function’s output with respect to the input. Derivatives are a fundamental tool of calculus. For example, the derivative of the position of a moving object with respect to time is the object’s velocity: this measures how quickly the position of the object changes when time advances.
