E is about 2.7 1828, that is, the formula is Iim (1+ 1/ x) x, X→< X>；; Or Iim (1+z) 1/ z, z →0, which is an infinite acyclic decimal and a transcendental number.

E is named after the Swiss mathematician Euler; There is also a relatively rare name Napier constant to commemorate the introduction of logarithm by Scottish mathematician John Napier. It is one of the most important constants in mathematics, just like pi and imaginary units I and E.

Origin:

1690, Leibniz first mentioned the constant e in his letter. The constant E mentioned for the first time in this paper is a table in the appendix of John Napier's logarithmic works published in 16 18.

But it didn't record this constant, only a list of natural logarithms calculated from it, which is generally believed to be made by William Oughtred. It was Jacob Bernoulli who first thought that E was a constant. Euler also heard of this constant, so at the age of 27, E was "guaranteed" to calculus by publishing a paper.