British science writer David Darling that the number e is " possibly the most important number in mathematics.
Although pi is more familiar to the layperson, e is far more significant and ubiquitous in the higher reaches of the subject.
The number e, which is approximately equal to 2.71828, can be calculated in many ways.
For example, is the limit value of expression (1+1/n) raised to the nth power, when n increases indefinitely.
Although mathematicians like Jacob Bernoulli and Gottfried Leibniz were aware of the constant, Swiss mathematician Leonhard Euler was among the first to extensively study the number, and he was the first to use the symbol e in letters written in 1727.
In 1737, he showed that e is irrational - that is, it cannot be expressed as a ratio of two integers.