Thales, the father of mathematics
Thales, born in 624 BC, was the first great mathematician in ancient Greece who enjoyed a world-renowned reputation. He used to be a shrewd businessman. After he accumulated considerable wealth by selling olive oil, Thales devoted himself to scientific research and travel. He is diligent and studious, at the same time, he is not superstitious about the ancients, and he is brave in exploration, creation and positive thinking. His hometown is not too far from Egypt, so he often travels to Egypt. There, Thales learned about the rich mathematical knowledge accumulated by ancient Egyptians for thousands of years. When he traveled in Egypt, he calculated the height of the pyramids in a clever way, which made the ancient Egyptian king Amerasis admire him very much.
Thales's method is ingenious and simple: choose a sunny day, erect a small stick at the edge of the pyramid, and then observe the change of the shadow length of the stick. When the shadow length is exactly equal to the length of the stick, quickly measure the length of the pyramid shadow, because at this time, the height of the pyramid is exactly equal to the length of the tower shadow. It is also said that Thales calculated the height of the pyramid with the ratio of the length of the rod shadow to the tower shadow equal to the ratio of the rod height to the tower height. If this is the case, it is necessary to use the mathematical theorem that the corresponding sides of a triangle are proportional. Thales boasted that he taught this method to the ancient Egyptians, but the fact may be just the opposite. It should be that the Egyptians knew a similar method a long time ago, but they were only satisfied with knowing how to calculate, without thinking about why they could get the correct answer.
Before Thales, people were only satisfied with how to explain all kinds of things when they knew nature, and Thales' greatness was that he not only could explain, but also added a scientific question mark on why. The mathematical knowledge accumulated by ancient orientals is mainly some calculation formulas summarized from experience. Thales believes that the formula thus obtained may be correct in one problem, but it may not be correct in another. Only when they are proved to be universally correct in theory can they be widely used to solve practical problems. In the early stage of the development of human culture, Thales consciously put forward such a view, which is commendable. It endows mathematics with special scientific significance and is a great leap in the history of mathematics development. So Thales is known as the father of mathematics, and that's why.
Thales first proved the following theorem:
1. The circle is divided into two by any diameter.
2. The two base angles of an isosceles triangle are equal.
3. Two straight lines intersect and the vertex angles are equal.
4. The inscribed triangle of a semicircle must be a right triangle.
5. If two triangles have one side and the two angles on this side are equal, then the two triangles are congruent.
This theorem was first discovered and proved by Cyrus, and later generations usually call it Cyrus theorem. According to legend, Thales was very happy after he proved this theorem and slaughtered a bull to worship the gods. Later, he also used this theorem to calculate the distance between the ship at sea and the land.
Thales also made pioneering contributions to ancient Greek philosophy and astronomy. Historians affirm that Thales should be considered as the first astronomer. He often lies on his back to observe the constellations in the sky and explore the mysteries of the universe. His maid often joked that Thales wanted to know the distant sky, but ignored the beautiful scenery in front of him. According to the research of Herodotus, a historian of mathematics, it is known that the day suddenly turned into night (actually a solar eclipse) after hals War, and Thales had predicted this before the war. There is an inscription on Thales' tombstone: "The tomb of the king of astronomers is a little small, but his glory in the field of stars is quite great. 」