I don't need to explain the beauty of Euler's formula. In mathematical and physical formulas, people often equate it with E = MC 2 of Lao Ai as a binary star. In history, Euler was an all-round mathematician and a devout believer in the existence of God. It is said that once Catherine II of Russia invited Diderot to visit her court, and Diderot was an atheist. Soon, Catherine II got tired of Diderot's endless atheistic preaching and asked Euler to teach him a good lesson. Euler came straight to the point and asked, "E I * PI+ 1 = 0 (that is, Euler's formula), so God exists, please answer!" As a result, Diderot, who didn't understand mathematics, was at a loss and was speechless.