Thầy cô cho em hỏi là tại sao tích phân bài này mà phá trị tuyệt đối lại bị đổi dấu hàm số vậy ạ

Câu 1: Trong những trường hợp nào thì thụ phấn nhờ người là cần thiết? Cho ví dụ. Câu 2: Phân biệt hiện tượng thụ phấn và hiện tượng thụ tinh. Thụ phấn có quan hệ gì với thụ tinh. Câu 3: Dựa vào đặc điểm nào để phân biệt quả khô và quả thịt? Hãy kể tên ba loại quả khô và ba loại quả thịt ở địa phương em.

Cho tam giác ABC cân tại A, đường AH vuông góc với BC, H thuộc BC ; Kẻ HD, HC lần lượt vuông góc với AB, AC. Trên tia đối của tia DH, EH lấy theo thứ tự điểm M, N sao cho DM = DH, EN = EH, Chứng minh : a/ AM = AN b/ AH là đường trung trực của MN c/ góc MAN =2. góc BAC

17. Choose the word that is CLOSEST in meaning to the word"HUGE" in the following sentence: The huge Olympic stadium in Beijing is called “The Bird’s Nest.” * A. rectangular B. new C. enormous D. tiny 18. Choose the word that is CLOSEST in meaning to the word"EXCELLENT" in the following sentence: She speaks excellent French. * A. good B. extremely good C. cool D. merry 19. Choose the word that is OPPOSITE in meaning to the word"IMPROVED" in the following sentence: Her health has improved dramatically since she met that doctor. * A. became quicker B. became better C. became slower D. became worse 20. Choose the word that is OPPOSITE in meaning to the word"Unfortunately" in the following sentence: The doctors try their best to save the wounded man. Unfortunately. he could not survive. * A. Ultimately B. Definitely C. Unbelievably D. Luckily 21. Choose the sentence that is almost the same in meaning as the sentence given: I came to live here three months ago. * A. It was three months since I lived here. B. I’ve been living here for three months. C. I lived here for three months. D. I didn’t live here for three months. 22. Choose the sentence that is almost the same in meaning as the sentence given: The teacher explained the rule to the student. * A. The rule was explained to the student. B. The students were explained the rule. C. The students were explained the rules. D. A and B are correct 23. Choose the sentence that is almost the same in meaning as the sentence given: They can’t work and travel because they are old. * A. Because of their old age, they can’t work and travel. B. In spite of their old age, they can work and travel. C. Despite their old age, they still work and travel. D. Even though they work and travel, they are old. 24. Choose the sentence that is almost the same in meaning as the sentence given: “ Stay in bed for a few days," the doctor said to him. * A. The doctor said to him stay in bed for a few days. B. The doctor said him to stay in bed for a few days. C. The doctor told him to stay in bed for a few days. D. The doctor told to him stay in bed for a few days. 25. Choose the sentence that is almost the same in meaning as the sentence given: Mary said, “ I want to give up my job.” * A. Mary said that she wants to give up her job. B. Mary said that I wanted to give up her job. C. Mary said that she wanted to give up my job. D. Mary said that she wanted to give up her job. 26. Choose the sentence that is almost the same in meaning as the sentence given: When I was younger, I used to go climbing more than I do now. * A. Now I don’t go climbing anymore. B. I used to go climbing when I younger. C. Now I don’t go climbing as much as I did. D. I don’t like going climbing any more. 27. Choose the sentence that is almost the same in meaning as the sentence given: You must work harder or you’ll be sacked. * A. Unless you work harder, you’ll be sacked. B. If you work harder, you won’t be sacked. C. If you don’t work harder, you won’t be sacked. D. A & B are correct. 28. Choose the sentence that is almost the same in meaning as the sentence given: Someone was breaking into my shop. * A. My shop was broken into. B. My shop being broken into. C. My shop was being broken into. D. My shop broken into. 29. Choose the sentence that is almost the same in meaning as the sentence given: I won’t do anything if you don’t answer my question. * A. Unless you answer my question, I won’t do anything. B. If you answer my question, I won’t do anything. C. Unless you don’t answer my question, I won’t do anything. D. A & B are correct. 30. Choose the sentence that is almost the same in meaning as the sentence given: We spent a whole day looking for these old pictures. * A. It took we a whole day to look for these old pictures. B. It took us a whole day looking for these old pictures. C. It took us a whole day to looking for these old pictures D. It took us a whole day to look for these old pictures.

5. Choose the correct option to complete the sentence: ______ youngest boy has just started going to ______ school. * A. A; x B. the; x C. x; the D. An; x 6. Choose the correct option to complete the sentence: Minh is a hard-working boy. He doesn’t mind ______ a lot of homework in the evenings. * A. making B. doing C. to make D. to do 7. Choose the correct option to complete the sentence: I wonder who live _______ , country folk or city people? * A. happier B. more happier C. happilier D. more happily 8. Choose the correct option to complete the sentence: ______ of you prefer hanging out with friends to watching TV? * A. Who B. What C. Which D. Whose 9. Choose the correct option to complete the sentence: This film is very interesting. I ________ it three times. * A. saw B. see C. have seen D. will see 10. Choose the correct option to complete the sentence: "Khen" is a ________ instrument of the Central Highland. * A. traditionally B. tradition C. traditional D. trade 11. Choose the correct option to complete the sentence: I think country life is so boring and ………… because you’re not close to shops and services. * A. unhealthy B. inconvenient C. comfortable D. peaceful 12. Choose the correct option to complete the sentence: We ………….. him since we left school. * A. don’t meet B. didn’t meet C. haven’t met D. hasn’t met 13. Find the mistake in the following sentence:The villagers often find it incoveniently to get into town due to the lack of public transport. * A. The villagers B. incoveniently C. due to D. lack of 14. Find the mistake in the following sentence: Hoa works very hardly so she always gets good marks. * A. works B. hardly C. so D. always gets 15. Choose the correct response: “My favourite leisure activity is people watching.” - “_______” * A. That sounds so weird! B. That’s all right. C. OK. That’s what you’ve chosen. D. Sure. It’s very entertaining. 16. Choose the correct response: “Where will you go on vacation?” - “...........................” * A. Probably to the beach. B. The beach is nice, isn’t it? C. Probably I won’t think of. D. I have a four-day vacation.

Cho hình bình hành ABCD, biết rằng với mọi điểm M luôn có: MA²+ MC²= MB² + MD² Chứng minh rằng ABCD là hình chữ nhật

Gọi S là tập nghiệm của BPT $\sqrt[]{5x-1}$ -$\sqrt[]{x-1}$ > $\sqrt[]{2x-4}$. Tìm phần bù của S

Trên mặt phẳng toạ độ Oxy Oxy , cho d_1: 4x +3y-2 = 0 d 1 ​ :4x+3y−2=0 và d_2: x +7y-1 = 0 d 2 ​ :x+7y−1=0 . Góc \widehat{\left(d_1,d_2\right)} (d 1 ​ ,d 2 ​ ) ​ bằng

So sánh sự giống và khác nhau giữa nguyên nhân dẫn đến CTTG thứ 1 và 2? 10 dòng thôi nhé!

Câu 1: a) Nêu 1 số trường hợp thực phẩm bị vi khuẩn có hại xâm nhập? b) Nêu thêm 1 số thực phẩm có chứa sẵn chất độc, 1 số trường hợp thực phẩm bị nhiễm chất độc từ bên ngoài c) Nguyên nhân có nhiều vụ ngộ độc thực phẩm?