At the turn of the eighth and ninth centuries, a great mathematician was born in Germany. He is called "the prince of mathematics" Gauss.

When Gauss was in elementary school, the math teacher once asked a question, 1+2+…+ 100=? See1+100 =10/,2+99= 10 1, …, 50+51=1.

Obsessed with mathematics and diligent in study, at the age of 18, Gauss invented the method of making regular 17 polygons with compasses and straightedge, thus solving the problem that has not been solved since 2000. 2/kloc-graduated from university at the age of 0, and received his doctorate at the age of 22. In his doctoral thesis, he proved the basic theorem of algebra, that is, the unary n-degree agenda must have roots in the complex number range. In geometry, Gauss is one of the inventors of non-Euclidean geometry. Gauss's most important contribution is number theory. His magnum opus Arithmetic Research marks that number theory has become an independent branch of mathematics, and the content discussed in this book has become the research direction of number theory until the 20th century. Gauss first used congruence notation, and systematically expounded the theory of congruence formula. He proved important results in number theory, such as the law of quadratic reciprocity. After the death of Gauss, people built a Gauss image on the basis of a regular 17 prism to commemorate this great mathematician.

Thales —— An Advocate of Rational Mathematics in the West

Thales, an ancient Greek scholar (624 ~ 547 BC), was born in a slave owner's noble family in Maitreya, Asia Minor. Thales doesn't pay attention to the family's political status and rich economic life, but puts all his energy into the study of philosophy and science. When he was young, he traveled around the world and went to the country of pyramids, where he learned astronomical observation and geometric measurement. I have also been to Babylon in the two river basins and learned a lot about the splendid culture of the East. After returning to his hometown of Miletus, he founded the Ionian School, which became the first of the seven famous schools in ancient Greece. Thales is known as "the father of science".

Thales has a famous saying: "Water is the source of all things, and all things are finally water." He denied the view that God created everything and created a correct way to know the world from the world itself. In science, he advocates rationality, is not satisfied with intuitive and perceptual expertise, and advocates abstract and rational general knowledge. For example, two isosceles triangles with equal base angles do not refer to a single isosceles triangle we can draw, but to "all" isosceles triangles. This requires argumentation and reasoning to ensure the correctness of mathematical propositions, so that mathematics is rigorous in theory and widely used. Thales' active advocacy laid the foundation for Pythagoras to establish rational mathematics.

Thales found many theorems of plane geometry in mathematics, such as "the diameter bisects the circle", "the angles between two sides of a triangle are equal", "two straight lines intersect and the vertex angles are equal", "the two angles and their sides of a triangle are known, and the triangle is completely determined", and "the angles of a semicircle are right angles" and so on. Although these theorems are simple, the ancient Egyptians and Babylonians may have known them for a long time, Thales organized them into general ones. It is said that he can use a benchmark to measure and calculate the height of the pyramid.

Thales also made extraordinary achievements in astronomy. It is said that he detected a total solar eclipse on May 28th, 585 BC. At that time, the war was in full swing, and Thales announced to the world that if there was no truce, the gods would be angry! By that afternoon, the two factions of soldiers were still fighting fiercely. In an instant, the sun disappeared in the sky, the stars flashed and the earth was dark. Seeing this, the soldiers of both sides were convinced that the sun god was really angry and wanted to punish mankind, so they immediately stopped fighting, forged swords into plowshares and lived in harmony.

According to another legend, Thales is obsessed with studying philosophy and science. He is poor and conservative, so he is laughed at by the public. He said disapprovingly that a gentleman loves money and takes it wisely. On the basis of climate prediction, he estimated that there would be a bumper harvest of oil crops in the coming year, so he monopolized all oil mills in Miletus and Caius and rented them at high prices during the harvest season. With money, scientific research can be done better.

If these two legends are true, Thales really deserves the eulogy engraved on his tombstone: "He is a saint and an astronomer. In the kingdom of the sun, the moon and the stars, he is indomitable and immortal. " However, this is also a legend, because Thales lives too far away from us and has no exact and reliable information.