E is the base of natural logarithm and an infinite acyclic decimal. You will know after learning advanced mathematics. log e=ln。 Generally used in calculations involving logarithmic operations, it is a mathematical symbol with no specific meaning.

e= 1+ 1/ 1！ + 1/2! + 1/3! +……+ 1/n！ +…… .

e≈ 1+ 1/ 1！ + 1/2! + 1/3! +……+ 1/n！ The greater the n, the better the approximation.