Đáp án:
Giải thích các bước giải:
`y=8sin\ x-cos\ 2x-3`
`y=8sin\ x-(1-2sin^2 x)-3`
`y=8sin\ x-1+2sin^2 x-3`
`y=2sin^2 x+8sin\ x-4`
`y=2(sin^2 x+4sin\ x-2)`
`y=2(sin^2 x+4sin\ x+4-6)`
`y=2[(sin\ x+2)^2-6]`
`y=2(sin\ x+2)^2-12`
Ta có: `-1 \le sin\ x \le 1`
`⇔ 1 \le sin\ x+2 \le 3`
`⇔ 1 \le (sin\ x+2)^2 \le 9`
`⇔ 2 \le 2(sin\ x+2)^2 \le 18`
`⇔ -10 \le 2(sin\ x+2)^2 -12 \le 6`
Vậy `y_{min}=-10`
`y_{max}=6`
$\begin{array}{l} y = 8\sin x - \cos 2x - 3\\ = 8\sin x - \left( {1 - 2{{\sin }^2}x} \right) - 3\\ = 8\sin x - 1 + 2{\sin ^2}x - 3\\ = 2{\sin ^2}x + 8\sin x - 4\\ = 2\left( {{{\sin }^2}x + 4\sin x + 4} \right) - 12\\ = 2{\left( {\sin x + 2} \right)^2} - 12\\ - 1 \le \sin x \le 1 \Rightarrow 1 \le \sin x + 2 \le 3\\ \Rightarrow 1 \le {\left( {\sin x + 2} \right)^2} \le 9\\ - 10 \le y \le 6\\ \Rightarrow \left\{ \begin{array}{l} \min y = - 10\\ \max y = 6 \end{array} \right.\\ \end{array}$
:)))))))) vẽ giùm một quả đào đi ah:)))) tiện đang chán cần ngừi tâm sự cùng:< cám ưnnnn;3
Vẽ 2 đường thẳng cắt nhau tính các góc còn lại a)40° b)73° c)28° d)59° e)72° f)105° g)137°
Làm dễ hiểu và đúng giúp em! 1. Một chiếc nón lá có độ dài đường sinh là 25cm, bán kính đáy 15cm. Tính thể tích của chiếc nón trên? 2. Một trường đã khảo sát 1500 học sinh về các sở thích của mình gồm hội họa, thể thao, âm nhạc và các yêu thích khác, nhưng mỗi hs chỉ được chọn một. Trong đó: -Số hs thích hội họa chiếm 20% so với số hs khảo sát. - Số hs yêu thích thể thao hơn số hs yêu thích âm nhạc là 30 em. - Số hs yêu thích thể thao và hội họa bằng số hs yêu thích âm nhạc và yêu thích khác. a) Tính số hs yêu thích hội họa b) Hỏi tổng số hs yêu thích thể thao và âm nhạc là bao nhiêu?
1. At this time yesterday we ( play) soccer in the schoolyard. 2. At 7 pm yesterday he ( watch) TV. 3. Yesterday while my father ( watch) TV, my mother ( read) the newspaper. 4. What you ( do) when I phoned you? I ( have) a bath. 5. She ( do) her homework at this time yesterday. 6.Marry ( water) the flowers at 3.pm yesterday? 7. They ( visit) the zoo at 10 o’clock yeMarry ( water) the flowers at 3.pm yesterday? sterday. 8. Peter and I ( not do) exercise at this time last night. 9. At 8am yesterday my sister ( feed) the pigeons. 10.At this time last year we ( learn) English in London.
Add giải hộ mình bài này với ạ, mình cảm ơn nhiều ạ
Cho A nằm bên ngoài đường tron (O). Qua A kẻ 2 tiếp tuyến tiếp xúc đường tròn (O) tại B và C. Gọi M và N lần lượt là trung điểm của AB và AC. a) Cm: MN vuông góc với OA b) Trên đường thằng MN lấy D. Qua D kẻ đường thẳng tiếp xúc (O) ở E. So sánh DE và DA
Giúp mình với cảm ơn ạ hứa vote 5*
Bài 2: Điền vào chỗ trống với các đại từ quan hệ: Who, Whom, Whose, Which, That, Where… 1. The men ………….lives next-door are English. 2. Do you know the girls ………….are standing outside the church? 3. The chocolate ………….you like comes from the United States. 4. A burglar is someone ………….breaks into a house and steals things. 5. I can’t find the key ………….opens this door. 6. I don’t like the boy ………….Sue is going out with. 7. The man ………….she is going to marry is very rich. 8. He wore a mask ………….made him look like Mickey Mouse. 9. The man ………….mobile was ringing did not know what to do. 10. The woman ………….daughter was crying tried to calm her down. 11. The family ………….car was stolen last week is the Smiths. 12. A bus is a big car ………….carries lots of people. 13. Children ………….like music are often good at mathematics. 14. The girl ………….recited the poem is my niece. 15. The Pacific Ocean, ………….might have been crossed by raft during the Stone Age, is the world’s largest ocean. 16. The parents thanked the woman………….had saved their son 17. Two men, neither of ………….I had been before, came into my office. 18. He ate the food ………….no one else wanted 19. The village …………. I ran out of petrol didn’t have a petrol station 20. John sold his computer, …………. he no longer need, to his cousin 21. The dictionary ………….you gave me is very good. 22. The police are looking for the thieve ………….got into my house last night. 23. I have lost the necklace ………….my mother gave me on my birthday. 24. Buses ………….go to the airport run every half hour. 25. I gave you a book ………….had many pictures. 26. Did you see the beautiful dress ………….she wore yesterday. 27. This is the bank ………….was robbed yesterday. 28. He arrived with a friend ………….waited outside in the car. 29. The car ………….the robbers escaped in was a BMW. 30. The postman ………….works in the village is very old. 31. The cowboy ………….is wearing a red shirt looks very funny. 32. The volunteers, ………….enthusiasm was obvious, finished the work quickly. 33. The engineers ………….designed the building received an award. 34. The townspeople, ………….pride in their community is well- known, raised enough money to build a new town hall. 35. The newspaper to ………….we subscribe is delivered regularly. 36. The factory …………. closed last week had been there for many years 37. I like the ice-cream …………. they sell in that shop 38. John has got a new mobile phone …………. takes photos 39. The job for …………. she has applied is in London 40. Teddy has two cars, one of …………. is very expensive.
II. BÀI TẬP MỆNH ĐỀ QUAN HỆ Bài 1: Chọn đáp án đúng nhất trong những câu sau: 1. Mr. Ken, …………. is living next door, is a dentist. A. that B. who C. whom D. what 2. The man ………….she wanted to see her family. A. which B. where C. whom D. who 3. The woman ………….came here two days ago is her professor. A. who B. that C. whom D. what 4. Freedom is something for ………….millions have given their lives. A. which B. where C. whom D. who 5. Blair has passed the exam last week, ………….is great news. A. who B. that C. which D. whom 6. The film about ………….they are talking about is fantastic. A. who B. which C. whom D. that 7. He is the boy ………….is my best friend. A. that B. whom C. who D. A& C 8. I live in a pleasant room ………….the garden. A. to overlook B. overlooking C. overlooked D. which overlooking 9. The pilot was the only man ………….after the crash. A.was rescued B. rescued C. rescuing D. to be rescued 10. I’ll see you near the post office ………….we met the other day. A. which B. where C. when D. why 11. The man…………. lives behind my house is a doctor. A.that B. who C. which D. whom 12. The old building………….is in front of my house fell down. A. of which B. which C. whose D. whom 13. Her computer ………….was my friend’s got broke. A. which B. whom C. who D. that 14. Her grandmother, ………….is 70, often takes exercise. A. what B. who C. where D. which 15. The really happy people are those ……enjoy their daily work. A. what B. who C. which D. where 16. My girlfriend loves tokbokki, ………….is Korean food. A. which B. where C. whom D. who 17. The book ………….is in the car is his brother’s. A. who B. that C. which D. whom 18. Peter, ………….I played video games with on the weekend, was younger than me. A.that B. who C. which D. whom 19. The people ………….for the bus in the rain are getting well. A. waiting B. to wait C. waited D. wait 20. I have a message for people ………….by the traffic chaos. A. to delay B. who delay C. delayed D. who delaying
nhanh lên ạ ,ai nhanh nhất mik vote 5 và chọn câu trả lời hay nhất
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