Đáp án:
Giải thích các bước giải:Hơi tắt nhé
B=(x-y+z-1)^2+(y-2)^2+2(z-3/2)^2+1990.5
suy ra min B=1990.5 khi x=z=1.5,y=2
Tìm tập xác định của hàm số lượng giác: 1. y=$\frac{2sinx+1}{cos²x}$ 2. y=$\frac{\sqrt[]{7-sinx}}{cos²x}$
MÌNH chia nhỏ câu hỏi đấy ạ!Mbg giúp toi nhes ^^
Vẽ đậu mầmthèm ăn hoặc đang ngủ trên app full màu và line nhoa 1 pic ko kí 1pic kí ạ thanks các pác nhìu vẽ có tâm hộ ạ
Bài 4 câu a vài câu B bài 3 ạ 2 câu thôi nhanh hộ mình ạ
Một ca nô xuôi dòng từ A đến B rồi đi ngược về A. Vận tốc ca nô là 15 km/h. Vận tố nước là 3km/h, AB dài 24 km a, Tính thời gian chuyển động của ca nô b, tuy nhiên khi quay về A đi đc 7,2 km thì hỏng ca nô, sửa mất 24 phút. Muốn về A đúng dự định thì phải đi với vận tốc bao nhiêu?
Calli: "Con dở" (có trang trí, 1 pic không kí ; có tâm)
làm hộ mik nhanh vs ạ thank trc nha
Bài 1: 1. He wishes he ……………… right now instead of attending university. A. works B. is working C. worked D. were working 2. Nick: Could you lend me some money? Jim: I wish I ……………… you some money, but I’m broke myself. A. can lend B. would lend C. could lend D. will lend 3. An: What are you doing later this afternoon? Binh: I wish I ……………… the answer to that question. A. knew B. know C. could know D. would know 4. I wish we ……………… a calculator to work out these numbers. A. have B. had C. will have D. are having 5. We can’t go along here because the road ……………… A. is repairing B. is repaired C. is being repaired D. repairs 6. The story I’ve just read ……………… Agatha Christie. A. was written B. was written by C. was written from D. wrote by 7. Some film stars ……………… difficult to work with. A. are said be B. are said to be C. say to be D. said to be 8. ……………… she works 16 hours a day. A. It is said that B. She is said that C. They are said that D. There is said that 9. His friends ………………. that he made up the whole story himself. A. believe B. are believing C. are believed D. were believed 10. There ……………… a secret tunnel between those two houses. A. people say is B. people say has C. is said to be D. is said to have Bài 2: 1. The child is believed ………………… a white pullover and blue jeans. A. that he is wearing B. that he worn C. to be wearing D. is wearing 2. It ………………… that the prisoner escaped by climbing over a wall. A. alleges B. is alleged C. is alleging D. has alleged 3. How ………………… before the first motorbike was imported? A. did people in Viet Nam travel B. would people in Viet Nam travel C. had people in Viet Nam travelled D. had people in Viet Nam been travelled 4. Ly Chieu Hoang ………………… the country before the Tran dynasty. A. rules B. ruled C. was ruling D. had ruled 5. When I ………………… back, things dramatically. A. come - changed B. came - changed C. came - had changed D. had come - had changed 6. The house was very quiet when I ………..… home. Everyone ……..…… to bed. A. got - went B. got - had gone C. had got - went D. had got - had gone 7. Tom ………………… when I ………………… at the party last night. A. already went - arrived B. already gone - arrived C. had already gone - had arrived D. had already gone - arrived 8. I ………………… a bit better after I………………… the medicine. A. had felt - took B. felt - had taken C. felt - took D. had felt - had taken 9. When Martin ………………… the car, he took it out for a drive. A. had repaired B. has repaired C. repaired D. was repairing 10. Your birthday party was the last time I ………………… myself. A. have really enjoyed B. really enjoyed C. had really enjoyed D. really enjoy -nhanh nha-
Cho tam giác ABC , góc B nhọn . Trên nửa mặt phẳng có chứa điểm A bờ BC , vẽ tia Bx vuông góc BC , trên đó lấy điểm D sao cho BD = BC . Trên nửa mặt phẳng có chứa điểm C bờ AB , vẽ tia BI vuông góc BA . Trên tia đó lấy điểm E sao cho BE=BA . Chứng minh : a) DA=ECB b) DA vuông góc EC
Vẽ đậu mầm học bài trên app full màu và line nhoa 1 pic ko kí 1pic kí ạ thanks các pác nhìu vẽ có tâm hộ ạ
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