CBSE Class 12-science Answered

e is a sometimes defined as the Euler's number. It is a very important mathematical constant whose value is approximately equal to 2.71828. The beauty of this constant is the derivate of e^x is the function itself and infact at x = 0, the derivative is 1. Furthermore, it is the limit of (1+1/n)^n as n reaches infinity, something that becomes very important to compound interest calculations. So, yeah like pi, it is an important constant in the mathematics world and helps define a lot of functions. 

 

Why is it so extensively used in calculus is simple as I told you - its is probably the only funciton whose derivate is the function itself  and that whats make it extremely easy to use this function in a lot of calculus problems.