HISTORY: Derivation is very important in mathematics especially in calculus.
Appeared by the end of the 16th century, this concept was developed during the 17th century, by a great German philosopher and scientist named Gottfried Wilhelm Leibniz (1646-1716) and also by a great English scientist and inventor named Sir Isaac Newton(1642-1727).
PART 1: Derivative at x = a
Definition:
Let us assume that f is a function that is defined in an internal P and such that: a ∈ P.
EXAMPLE: Suppose, we have to find the derivative of function f at x = 3
