Chứng minh rằng với tứ giác ABCD bất kì ta luôn có: vecto AB- vecto CD =vecto AC- vecto BD. Em có thể tìm được bao nhiêu cách chứng minh?

Các câu hỏi liên quan

Kết hợp hai câu lại với nhau dùng đại từ quan hệ. 1. The doctor is with a patient. The patient’s leg was broken in an accident. → 2. Jane is the woman. Jane is going to China next year→ 3. Janet wants a typewriter. The typewriter self corrects. → 4. I found this book last week. The book contains some useful information. → 5. Mr. Bryant’s team has lost the game. He looks very sad. → 6. James wrote an article. The article indicated that he disliked the President. → 7. The director of the program is planning to retire next year. The director graduated from Harvard University. → 8. This is the book. I’ve been looking for this book all year. → 9. William wants to become a judge. William’s brother is a lawyer. → 10. The last record became a gold record. The record was produced by this company. → 11. Checking accounts are very common now. The Checking accounts require a minimum balance. → 12. Felipe bought a camera. The camera has three lenses. → 13. Frank is the man. We are going to nominate Frank for the officer in the school (nominate sb for/to a post = appoint ) 14. She is the woman. I wrote to her. → 15. They’re the people. I was talking about them. → 16. John received a scholarship. John’s grades are the highest in the school. → 17. That is the dog. I was afraid of it. → 18. Mr Cox is the manager. I am phoning for him. → 19. That is the tunnel, He went through it. → 20. She is the lady. He argued with her. → 21. She is the policewoman. The driver spoke to her. → 22. That is the mistake. I am complaining about it. → 23. He is the man. The novel was written by him. → 24. That is the shop. I bought a radio from it. → 25. Mr Cox is the manager. He saw Ann. → 26. Those men saved my life. They pulled from the burning car. → 27. That woman travels everywhere by private plane. She is a millionaire. → 28. That hotel’s near the beach. It’s the most expensive. → 29. Those birds migrate to Antartica. They breed near the North Pole. → 30. He is the criminal. The police are looking for him. → 31. These are the books. I use them in class. →