Need of the Derivatives:

If we want to know how something changes in time, we generally need to invoke a derivative.

This could be like the position of an object, the strength of an electric field, quantity of the water in the container,

the amount of the money in our bank account etc.

Need of Limit:

Limit helps us to understand what is means to get arbitrary close to the point or go to infinity.

The limit helps us to move from the study od discrete quantity to continuous quantity.

Nee of Calculus:

One of the most common use of the calculus in our daily life is the PID (Proportional integral Derivation) controller.

It has many applications:

1. Automatic air conditioner

1. Coffee machines

3. Cruise control in cars

4. Water mixers

5. Online advertisements

6. Industrial control systems, ships, missiles, rockets, UAV, etc.