Thales (an ancient Greek mathematician and astronomer) came to Egypt. People wanted to test his ability, so they asked him if he could measure the height of the pyramids. Thales agreed, but on one condition-Pharaoh must be present. The next day, Pharaoh arrived as scheduled and many onlookers gathered around the pyramid. Before Cyrus 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 made a mark on the projection of the Great Pyramid on the ground, and then measured the distance from the bottom of the Pyramid to the top of the projection tower. In this way, he reported the exact height of the pyramid. At the request of Pharaoh, 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.

Isaac Barrow (1630- 1677) is a famous British mathematician. He is a professor of mathematics at Cambridge University and has made great achievements in geometry. He was also a famous priest and wrote a lot of famous sermons. He was modest and amiable, but he had an indissoluble enmity with Count Rochester, the favorite of the King of charles ii at that time. As long as we meet together, there will inevitably be a war of words.

Rochester is said to have ridiculed Reverend Barrow as "a musty seminary".

One day, Barrow prayed for the king and met Rochester.

Rochester bowed deeply to Barrow and said sarcastically, "Doctor, please help me tie my shoelaces."

Barrow replied, "I ask you to lie on the ground, sir."

"Doctor, I invite you to the center of hell."

"Sir, please stand opposite me."

"Doctor, I invite you to the deepest part of hell."

"No, sir, such an elegant palace should be reserved for people of your status!" Say that finish, barrow shrugged and walked away.

The mystery of the inscription

Diophantu, a famous mathematician in Alexandria, ancient Greece, only knew that he was from the 3rd century A.D., and his age and life history books were not clearly recorded. However, we can still learn a thing or two from his tombstone, which tells people all the year round that he is 84 years old.

The tombstone of Diophantine is like this:

Diophantine is buried here. If you understand the mystery of the inscription, it will tell you the life span of Diophantine. The gods gave him 1/6 of life as his childhood. After112 of life, he grew a beard, and then Diophanto got married, but he had no children, so he lived 1/7 of life again. Five years later, he had his first son, but his beloved son died young.

The will of mathematicians

The will of Arab mathematician Hua Razmi, when his wife was pregnant with their first child. "If my dear wife gives birth to a son for me, my son will inherit two thirds of the inheritance and my wife will get one third; If it is a girl, my wife will inherit two-thirds of the inheritance and my daughter will get one-third. " .

Unfortunately, the mathematician died before the child was born. What happened after that made everyone more troubled. His wife gave birth to twins, and the problem happened in his will.

How to follow the mathematician's will and divide the inheritance among wife, son and daughter?

Not a bathhouse.

Amy Nord, a German mathematician, got a doctorate, but she is not qualified to teach because she needs to write another paper before the professor will discuss whether to grant her the qualification as a lecturer.

Hilbert, a famous mathematician at that time, appreciated Amy's talent very much. He ran around asking for permission to be the first female lecturer at the University of G? ttingen, but there was still controversy at the professor meeting.

A professor said excitedly, "How can a woman be a lecturer?" If she is allowed to be a lecturer, she will become a professor in the future and even enter the university Council. Can women be allowed to enter the highest academic institutions of universities? "

Another professor said, "How do our soldiers feel when they come back from the battlefield and find themselves prostrating themselves at the feet of women?"

Hilbert stood up and firmly refuted: "gentlemen, the gender of the candidate should never be an argument against her becoming a lecturer." After all, the university Council is not a bathing hall! "

Can only be single for life.

When alexander humboldt, an outstanding German naturalist, visited Lobachevsky, the founder of Russian non-Euclidean geometry in Kazan, he asked the mathematician, "Why do you only study mathematics? It is said that you have a deep understanding of mineralogy and are proficient in botany. "

What, you only study math? It is said that you have a deep understanding of mineralogy and are also proficient in botany. "

"Yes, I like botany very much," Lobachevsky replied. "When I get married in the future, I will definitely build a greenhouse ..."

"Then get married quickly."

"But contrary to my wish, my interest in botany and mineralogy has made me a bachelor all my life."

Bad Fox and Triangle

The hen hatched four chicks. She was happy and worried. Happily, all four chicks are jumping, which is really pleasing; The worry is that the bad fox will steal the chicken.

In order to prevent the bad fox from stealing chickens, the hen found many boards and sticks and built a flat-topped cabin. Mother hen thinks that she is not afraid of bad foxes when she has a house.

Late at night, the fields were quiet. In the moonlight, a black shadow quickly ran near the cabin.

"Bang, bang!" The knock at the door woke the hen. "who?" Asked the hen.

"It's me, it's my husband's chicken. Open the door quickly. " A very ugly voice is answering.

The hen thinks: No! Husband's chicken is out of town, and it will take many days to come back. Besides, this ugly voice is not the voice of the husband chicken at all. The hen said loudly, "You are not an old hen, you are a bad fox. Go away quickly!" " "

When a bad fox can't be fooled, he shows his ferocious face. He snapped, "Give me the chicken! Or I'll tear down your house and eat you all! "

Although the hen was afraid, he said, "No, no, no! My chicks can't be eaten for you. "

The bad fox was furious and shook the flat-topped wooden house hard. Four chickens were so scared that they hid under the hen's wings. After shaking for a while, the frame of the house tilted. There was a big crack between the roof and the wall. A big fox's paw came in and caught a chick and ran away.

At dawn, birds fly around looking for food. A cry alarmed them.

Little yellowbird asks, "Hen, why are you crying?"

The hen cried and said, "I built a flat-topped wooden house to prevent bad foxes from stealing chickens." Who knows that the flat-topped wooden house is not strong, so the bad fox pushed it three times and two times. The bad fox caught a chick, blare ... "

The woodpecker said, "Little magpie can build a house. Please ask him to help you build a strong house!" " "

After a while, the woodpecker invited the magpie. The magpie said, "I can only build nests. Where can I build a house?"

"What shall we do?" Everyone is worried.

The magpie said, "Once I was in a big tree, I heard several builders say that the triangular roof is the strongest."

The woodpecker said anxiously, "Who has seen what a triangle looks like?"

The magpie made a triangle from three branches.

Everyone said, "Let's build it like this."

Some birds are holding branches, some are holding mud, woodpeckers are pecking holes in the wood, and magpies are tying up all the wood with twigs. When the sun went down, a new house with a triangular roof was built.

In the evening, the bad fox came again. This time, he said nothing and shook the wooden house desperately. Strange, why can't this wooden house shake tonight? ! The bad fox shook it again with all his strength, but it still did not move.

It's almost dawn, and the bad fox said bitterly, "Even if I spare you now, I'll come back tomorrow." If you dare to come out, I will eat you! " "

Early in the morning, the bird saw the hen worried about guarding the cabin again.

Little Shan Ying asked, "Mother hen, your cabin is very nice. What are you worried about? "

The hen said, "the triangular roof is safer, but we can't always stay in the house!" The bad fox said he would catch the chicks as soon as we came out. "

The lark said, "I have a good idea. We helped mother hen fence the house and install a wooden fence door to get in and out. Isn't this a good way to prevent bad foxes? "

Everyone said it was a good idea, so they started to build a wooden fence together. They also sharpened the top to prevent bad foxes from jumping in. Finally, install a rectangular wooden fence door.

At night, the bad fox really came again. He saw the baby chicken jumping around in the fence, drooling. The bad fox turned around the wooden fence twice and found that it was the easiest to break the fence door. He shook the wooden fence door with two claws. As a result, the rectangular door became a parallelogram, revealing a gap. The bad fox jumped in. I'm afraid it will be a disaster if the hen doesn't bring the chick to the house quickly.

The bad fox is gone. The little magpie flew in and said, "Rectangular doors are easy to deform. Nail a board diagonally and turn it into two triangles, which will be much stronger. "

The lark said, "We can't always guard against bad foxes. We should do this ... like this. " Everyone was very happy and busy for a while before leaving.

The bad fox came quietly again without eating the chicks. He went straight to the wooden fence door and shook it vigorously. Hey, why can't you shake it this time? The fox shook it with all his strength and fell into the trap with a splash. The bottom of the trap was covered with triangular spikes, and the sly fox died.

The hen said happily, "triangles are really useful!" "