Đáp án + Giải thích các bước giải:
Kẻ tia `Ot` sao cho `Ax////Ot////By`
Vì `Ax////Ot` (đề cho)
`=>xAO=AOt` (so le trong)
Mà: `xAO=30^o` (đề cho)
`=>AOt=30^o`
Vì `Ot////By` (đề cho)
`=>tOB+OBy=180^o` (trong cùng phía)
`=>tOB=180^o -OBy`
`=>tOb=180^o -150^o=30^o`
Ta có: `AOt+tOB=AOB` (cách vẽ)
`=>AOB=AOt+tOB`
`=>AOB=30^o +30^o=60^o`
Vậy `AOB=60^o`
Đáp án:
Kẻ Oz // Ax, Oz nằm giữa OA và OB
Ta có:
`hat{xOA} = hat{AOz} ( = 30^o)` ( 2 góc so le trong)
Từ $\begin{cases} Oz // Ax\\Ax // By \end{cases}$ ⇒ Oz // By
`hat{OBy} + hat{zOB} = 180^o`( 2 góc trong cùng phía bù nhau)
`150^o + hat{zOB} = 180^o`
` hat{zOB} = 180^o - 150^o = 30^o`
Lại có:
`hat{AOB} = hat{AOz} + hat{zOB}` (Oz nằm giữa OA và OB)
`hat{AOB} = 30^o + 30^o = 60^o`
Vẽ đậu mầm .
viết các đa thức sau thành tổng của 2 bình phương a, x^2+2y^2-2xy-2x+2 b, 2x^2-2x+13 c, 3x^2+2x+3 hay viet cac gia tri cua da thuc thanh tổng của 2 bình phương ko chép mạng nha ,
Các bạn giúp mình với ạ, làm nhanh, đúng tick 5 sao+ CTLHN nha
giúp với mn ơi mik đang cần gấp lắm nha
Question 8: Which of the following sentences is grammatically correct? A. The terrible noise made me jump. I just wanted to run away. B. The seaside village destroyed by the tsunami last year. C. Pollution is getting badder because of what we have done to the environment. D. He seems interesting in bungee jumping, but I know he’s scaring of heights.
5. It is very dangerous to walk alone after 10 pm in that park. You _____________________________________ 6. Antarctica is colder than any other place in the world. Antarctica is _____________________________________ 7. Remember to bring the compass: if not we will get lost in the forest. You must _______________________________________ 8. Doing morning exercises every morning is good for you. You ____________________________________________ 9. My father has a plan to repaint our house before Tet. My father _______________________________________ 10. I wanted to go. He wanted to stay. (but) _______________________________________________ 11. Your arguments are strong. They don’t convince me. (so) _______________________________________________ 12. She doesn’t use much suncream. She has very pale skin. (although) _______________________________________________ 13. Would you like to go to Paris? Would you rather go to Budapest? (or) _______________________________________________ 14. He’s very tired today. He went to bed very late last night. (because) _______________________________________________ 15. Cartoons are colourful and funny: that's why children enjoy watching them. Children enjoy watching cartoons ___________________ 16. I am going to have a test tomorrow; I can't watch the cartoon. I am going to have a test tomorrow __________________ 17. I haven’t visited my family since 2005. (time) The _____________________________ my family was in 2005. 18. My parents moved to New Zealand in 2010. (lived) My parents _____________________________ since 2010. 19. I think that no city is more beautiful than Paris. (most) I think Paris _____________________________ in the world. 20. The computer was too expensive for me to buy. (enough) I _____________________________ money to buy the computer. 21. She is very shy, so she doesn’t enjoy the party. If _____________________________________________ 22. He began learning English three years ago. He has _________________________________________ 23. Very few cities in Vietnam are as rich as Da Nang. Da Nang is one of the _____________________________ 24. Although it was noisy, we continued to study our lesson. In spite of ______________________________________ 25. The last time they visited Europe was two years ago. (not) They ________________________________________ 26. Robots are not as intelligent as humans. (than) Humans _____________________________________ 27. How long have you learned English? (start) When _______________________________________
Giải phương trình sau $3cos2x + 8sin3xcosx + 16cosx = 4sin4x + 22sinx + 23$
B1, Một mảnh đất hình thang có đáy bé là 150m, đáy lớn bằng 5/3 đấy bé, chiều cao bằng 2/5 đáy lớn . Hỏi diện tích mảnh đất bằng bao nhiêu mét vuông, bao nhiêu héc - ta? B2, Lúc 6h, 1 ôtô chở hàng từ từ A với 45km/h. đến 8h 1 oto du lịch cx ik từ A với vận tốc 60km/h và ik cùng chiều vs ôtô chở hàng. hỏi đến mấy h oto du lịch đuổi kịp oto chở hàng? B3, Tìm số tự nhiên thik hợp của X sao cho : 4/X = 1/5
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