Giải thích các bước giải:
Theo bài ra ta có:`A = 4 + 2^2 + 2^3 + 2^4 +.....+ 2^20``=>2A=(4.2) +( 2^2. 2 )+( 2^3. 2) +( 2^4 . 2)+.....+( 2^20. 2)``=>2A = 8 + 2^3 + 2^4 +....+2^21``=>2A - A =( 8 + 2^3 + 2^4 + 2^5 +....+2^21 ) - ( 4 + 2^2 + 2^3 + 2^4 + ...+2^20 )``=>A = 8+2^21 - 4- 2^2 ``=2^21+8-4-4``=2^21+8-8``=2^21+0``= 2^21``=>`A là lũy thừa của 2Vậy A là lũy thừa của 2
Đáp án:
A = 4 + 2^2 + 2^3 + 2^4 +.....+ 2^20
2A = 8 + 2^3 + 2^4 +....+2^21
2A - A =( 8 + 2^3 + 2^4 + 2^5 +....+2^21 ) - ( 4 + 2^2 + 2^3 + 2^4 + ...-+2^20 )
2A - A =( 8 + 2^3 + 2^4 + 2^5 +....+2^21) - 4 - 2^2 - 2^3 - 2^4 - ...- 2^20
A = 8+2^21 - 4- 2^2 = 8 + 2^21 - 8 = 2^21
Kết luận : A là lũy thừa của 2
Giúp mình 3 bài này với cần gấp ạ
viết lại câu , bài 5 1. He is carrying out a research on how people spend their money for clothes. → A research 2. Although I had all the necessary qualifications, they didn’t offer me the job. → Despite 3. “Please do not litter as you are walking along the coast”, the guard said to us. → The guard told 4. I haven’t bought any clothes since my trip to Hanoi. → The last time 5. They think that a garden would be a perfect setting for the house. → It 6. Jack’s parents made him study a lot for the entrance exam to high school. → Jack was 7. You can’t register for a course abroad if you don’t have a passport. → Unless 8. “Why don’t we visit the Royal Citadel first?” Quang said. → Quang suggested that 9. People expect that he will join the company soon. → He 10. Shall we use Perfume Pagoda as a theme of the presentation? → She suggests
Cali: Wake Digi, tradi nhận hết. Có tâm giúp với ạ ^^! Nhận đẹp thoy nha;-;;
60đ đấy .... Nên giải thích rõ ràng hộ me Giải thích kiểu lớp 6 Nhanh nhất = hn
Ai giúp mình làm bài này nhé, hơi khó. Mình cảm ơn trc
chỉ ra hành động nói của câu in đậm cô bảo ko phải hđ hỏi vì câu sau ko có câu tl ;-;
III. Điền vào chỗ trống các từ: a few, a little, much, many: 2. He drank too …………… beer last night. 3. There were too …………… people in front of the theater. 4. She has a lot of books, but only ……………… books are interesting. 5. You made so …………… mistakes in your writing. 6. He never spends too ………… money on his vacation. 7. I only have ………… beefsteak in my plate. Please give me more. 8. Please wait a minute. I want to ask you …………… questions
Các bạn giúp mình với Trình bày chi tiết nha
Bài này là bài kia đấy ạ Các anh chị làm luôn cho em với ạ
bài 5 1. The limestone formation of Thien Duong Cave is more than that of PhongNha Cave. a. spectacular b.probable c. geological d. sight-seeing 2. During PerfumePagoda festival, alarge number of flocktothe pagodatopray for happiness and prosperity in the coming year. a. spectators b.passengers c. pilgrims d. travellers 3. In the 17th century, the Viet people the temple tower, calling it Thien Y ThanhMau Tower. a. put on b. looked for c. got into d. took over 4. The police caught the thief the corner of Cascade and Plum Streets. a. under b. at c. on d. in 5. He suggests that they should adopt a different way of bringing uptheir children. a. parents b. for parents c. toward parents d. to parents 6. If there is a mechanical problem, we suggest the manufacturer directly. a. contact b. to contact c. contacting d. to contacting 7. It is that the best time to visit Hanoi is September. a. believed b.worth c.rumored d. wondered 8. It that Po Nagar Cham Towers were built in the 8th century. a. considered b.was considered c. has considered d. considers 9. I suggest you Ha Long Bay. It’s very picturesque. a. to visit b.visiting c.visited d. should visit 10. A: You really must go to Hoi An to enjoy the full moon at Mid-autumn Festival. B: . a. Yes, that’s what I’ve heard. b. Do you really know about it? c. Yes, I won’t go there. d. No, thank you. 11. “Watch out, boy!” It means ……………… A. Look up, boy! B. Be careless, boy! C. Be carefully, boy! D. Be careful, boy! 12. The scenery is ……………… when viewed from the mountain top. It feels like your breath is being taken away. A. spectacular B. good C. nice D. peaceful 13. We used ……………… the kites when we were small. A. to fly B. fly C. flew D. flying 14. …………… by the sea, the country has the advantage of having a large coastal area. A. Stood B. Located C. Locating D. Situating 15. I love it when we go to see plays, and try to ……………… when we get back home. A. act B. play C. act them out D. role-play 16. ……………… I was talking to my teacher, my friends were waiting for me outside the classroom. A. While B. Although C. In order that D. Meanwhile 17. It is important to decide if promotion should be based on merit or ……………… A. seniority B. year C. gender D. weight 18. “What’s the best way to get around Hoi An town?” - “ ……………… “ A. That’s useful B. It’s worth seeing C. Great, thanks D. I suggest walking 19. She turned ……………… the new job in New York because she didn’t want to move. A. on B. down C. off D. up 20. This city has one of the most ……………… underground rail networks in the world. A. efficient B. fashionable C. cosmopolitan D. fascinated
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