Đơn giản các biểu thức : a) A= cos(a+b)+sinasinb / cos(a-b)-sinasinb

Câu 1 : Hoàn thành các câu sau. He said to me”I haven’t finished my work” ”What are you talking about?”said Mr.Huong ”Don’t talk in class”, Mr.Huong said to us

Giải câu 1 ý 2 phần b tìm a sao cho A=-a^2 Và giải hết câu 2 ạ

Bài 5: Cho tam giác ABC vuông tại A có AB = 6cm, BC = 10cm, đường cao AH . a) Chứng minh ABCđồng dạng HAC. b) Tia phân giác của góc ABC cắt cạnh AC tại I. Tính IC. c) Qua C kẻ đường thẳng vuông góc với BI tại K. Gọi E là giao điểm của BA và CK. Chứng minh rằng EA.EB = EC.EK từ đó suy ra tam giác EAK đồng dạng tam giác ECB d) Gọi D là hình chiếu của K trên BE. Chứng minh rằng: (BK/KE)^2=BD/DE

A =1\2.5 + 1\5.8 + 1\8.11 + ... +1\92.95 + 1\95.98

Em hãy nêu một số phương pháp học tập dem lại hiệu quả nhất cho bản thân?

II/ Rearrange the words to make reported sentences. 1. asked/was/how much/that/Tom/computer Tom..................................................................................................................................2. had/to know/the officer/if/wanted/the keys/I The officer ...................................................................................................................... 3. Ann/hadn’t come/why/to her party/asked/Sam/he Ann ................................................................................................................................ 4. asked/Jane/for her holidays/she/was going/he/where He.....................................................................................................................................5. me/English/asked/I/spoke/He/if He .................................................................................................................................... 6. old/asked/He/her/how/was/mother He ............................................................................................................................ 7. British/was/asked/whether/He/I/me/American/or He ................................................................................................................................. 8. Boy/The asked/the/where/lived/policeman/be The policeman................................................................................................................ 9. Had/Bristol/She/I/been/asked/to/before/if She.................................................................................................................................. 10. The/asked/time/train/She/what/arrived. She ................................................................................................................................. III/ Choose the best correct answer. 1. Tourist: “Where is the post office?” A tourist asked me where ............................... A. the post office has B. the post office was C. is the post office D. was the post office 2. Mom: “It’s 2 a.m; what are you doing in the kitchen?” Mom wanted to know what ...................... in. A. was I doing B. I do C. I was doing D. am I doing 3. Dad: “Why did you come home so late last night?” Dad wanted to know ................ home very late the night before. A.why did I come B. if I come C. if I came D. why I had come 4. Jane: “Have you ever been to Australia?” Jane asked me .......................to Australia A. if I’m ever going B. if I’d ever been C. have I ever been D. had I ever been 5. Joe: “Could you sing when you were five?” He asked me.................when I was five A. can I sing B. if I can sing C. could I sing D. if I could sing 6. Mother: “When are you going to do your homework?” Mother asked me when ...........to do my homework. A. was I going B. I was going C. am I going D. I’ll be going 7. Allen: “How many songs had John Lennon written before he died?” Allen wanted to know how many songs .................. before his death. A. John Lennon had written B. John Lennon was writing C. was John Lennon writing D. had John Lennon written 8. Janet: “Were you working at 8p.m last night?” Janet asked me ................... at 8p.m the other night. A. if I’m working B. if I’d been working C. was I working D. had I been working 9. Dad: “Have you been attending classes regularly?” Dad asked me ...................attending classes regularly. A. if I’d be B. had I been C. if I’d been D. have I ben 10. Mario: “What should I do to improve my English?” Mario asked his teacher what ........... to improve his English. A. he should do B. he would do C. shall he do D. should he do 11. Jim: “How much does your sister earn?” Jim wanted to know how much................. A. my sister has earned B. did my sister earn C. does my sister earn D. my sister earned 12. Joe: “Could you sing when you were five?” He asked me ....................when I was five. A. can I sing B. if I can sing C. could I sing D. if I could sing 13. Mary: “Are you able to swim?” Mary asked me ........................to swim. A. if I have been able B. am I able C. if I was able D. will be able 14. Tourist: “When was that castle built?” The tourist asked the guide when ................... A. had the castle been built B. the castle had been built C. the castle was being built D. was the castle built 15. Sue: “May I sleep at Lee’s house overnight?” Sue asked her mother ........................ at her friend’s house overnight A. if she might sleep B. could she sleep C. can she sleep D. if she had to sleep

Tại sao quả bóng bàn đang bị bẹp khi nhúngvaof nước nóng lại có thể phồng lên,?

các anh cj giúp em câu V và VI với ạ em cảm ơn nhìu

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