Ju Lushi (an ancient Greek mathematician and astronomer) came to Egypt. People want to test his ability and ask him if he can measure the height of the pyramid. Thales agreed, but on one condition-Pharaoh must be present. The next day, Pharaoh arrived as promised, and many onlookers gathered around the pyramid. Before Qin Le came to the pyramids, the sun cast his shadow on the ground.

Every once in a while, he asked someone to measure the length of his shadow. When the measured value is completely consistent with his height, he immediately marks the projection of the Great Pyramid on the ground, and then measures the distance from the bottom of the Pyramid to the projection spire. In this way, he quoted the exact height of the pyramid.

At the request of Lao Wang, he explained how to push the principle from "shadow length equals body length" to "tower shadow equals tower height". Which is today's similar triangles theorem.

2. The number "0"

About 1500 years ago, European mathematicians did not know how to use "0". They use Roman numerals. Roman numerals are symbols representing numbers, which are combined to represent different numbers according to certain rules. When using this number, the number "0" is not needed. At that time, a scholar of the Roman Empire discovered the symbol "0" from Indian notation.

He found it very convenient to use "0" for mathematical operation, and he was very happy. He also introduced how Indians use "0". After a while, it was known by the pope at that time. At that time, it was the Middle Ages in Europe. The power of the church was very strong, and the power of the pope far exceeded that of the emperor. The Pope was very angry. He rebuked that the sacred numbers were created by God.

There is no monster "0" in the number created by God. Now anyone who wants to introduce it is blasphemy! So the Pope ordered the scholar to be arrested and tortured, and his ten fingers were tightly clamped with a clamp, making his hands disabled and unable to write with a pen. In this way, "0" was banned by the stupid and cruel Pope.

But ... although it is forbidden to use "0", Roman mathematicians still use "0" secretly in mathematical research regardless of the ban, and still make a lot of mathematical contributions with "0". Later, "0" was finally widely used in Europe, but Roman numerals were gradually eliminated.

3. Tian Ji horse racing

During the Warring States Period, Qi Weiwang and Tian Ji raced, and Qi Weiwang and Tian Ji each had three good horses: getting on, winning and dismounting. The race is divided into three times, and thousands of dollars are bet on each horse race. Because the horsepower of the two horses is almost the same, and Qi Weiwang's horse is better than Tian Ji's, most people think that Tian Ji will lose.

However, Tian Ji took the advice of his disciple Sun Bin (a famous strategist) and dismounted Qi Weiwang's horse, Ma Zhong of Qi Weiwang and Qi Weiwang. As a result, Tian Ji beat Qi Weiwang 2-/kloc-0-and won a lot of money. This is an example of China's ancient substitution game theory to solve problems.

4. Archimedes principle

The king made a golden crown. He suspected that the craftsman had stolen some gold with silver, so he asked Archimedes to identify whether it was made of pure gold and not to damage the crown. Archimedes thought hard about the crown all day. One day, Archimedes went to the bathroom to take a bath. He stepped into the bath bucket, and when he immersed himself in the bath bucket, some water overflowed from the side of the bucket.

Archimedes saw this phenomenon, and his mind was like a flash of lightning. "I found it!" " "Archimedes put a gold nugget with the same weight and a silver nugget with the same weight into a container filled with water, and found that the silver nugget discharged much more water. So Archimedes took a gold nugget with the same weight as the crown and put it in a container filled with water to measure the displacement;

Then put the crown in a container filled with water to see if the amount of water discharged is the same, and the problem will be solved. With further research, Archimedes principle, the most important cornerstone of fluid mechanics, was born.

5. Gauss does math problems

When Gauss was still in the second grade of primary school, one day his math teacher wanted to use class time to deal with some personal affairs, so he planned to give the students a difficult problem to practice.

His topic is:1+2+3+4+5+6+7+8+9+10 =?

Because addition has just been taught, the teacher thinks it will take a long time for students to solve this problem. I can also take this opportunity to deal with unfinished business. But in the blink of an eye, Gauss had stopped writing and sat there doing nothing. The teacher saw it and called Gauss angrily. But Gauss said he had figured out the answer, which was 55. The teacher was startled and asked how Gauss worked it out.

Gauss replied, "I just found out that the sum of 1 and 10 is the sum of1,2 and 9,1,3 and 8,1/kloc-0. And because11+1+11+11= 55, that's how I worked it out. " Hearing this, the teachers and students all gave Gauss a thumbs-up. Later Gauss grew up and became a great mathematician.