In the history of mankind, there are three famous mathematicians who are called "the three mathematicians in history". Can be called great. One is Archimedes, one is Newton, and the third is Gauss. Someone asked, who is the fourth place? He is the great mathematician leonhardt? Euler. There are many scholars in history, such as Aristotle. We call him an encyclopedic scholar. For example, lomonosov of Russia, we also call him an encyclopedic scholar. As for Russell in modern England, he is even called an "encyclopedic wise man". Euler is not an encyclopedic scholar, but he has a brilliant name, which shows that his specialty is genius and great. Euler is called "an encyclopedic mathematician".