**DERIVATIVE**

It has many uses including instantaneous rate of change, slope of the tangent line and elasticity in economics.

For example if you are driving a car at 60 km per hour and drive for 2 hours you travel a distance of 120 km.

Sometime during the trip you were probably traveling at 70 km per hour and at other moments you were stopped for a traffic light. However you averaged 60 km per hour!

The derivative will tell you your exact speed (rate of change) at 1 hour 23 minutes and 34.99 seconds.

The difference between y_{2} and y_{1} is called delta y and the symbol is **∆y
The
difference between x**