Cho(O) và điểm A nằm ngoài (O). Kẻ tiếp tuyến AB, AC ( B,C tiếp điểm). Gọi H là trung điểm BC. a, Chứng minh: A,H,O thẳng hàng. b, Kẻ đường kính BD của(O). Vẽ CK vuông góc với BD. c, Tia AO cắt (O) tại M(M nằm giữa A và O). Chứng minh M là tâm đường tròn nội tiếp tam giác ABC. d, Gọi I lad giao điểm của AD và CK. Chừn minh I là trung điểm CK

Cho 3 số a;b;c khác 0, t/m ab+bc+ca=0 .Tính B= bc/ $a^{2}$ + ca/ $b^{2}$ + ab/ $c^{2}$

trong phòng TN ,người ta đun nóng hết 3,16 gam kali pemanganat để thu khí ôxi.Viet PTHH? Tính khối lượng khí oxi thu được ở đktc

Tìm điều kiện của các số nguyên a,b để ta có phân số : a) a+1/b mũ 2 +1 b)2b+1/a mũ 2 + 1 Ccá bạn giúp mk với !

Cho 9,2 gam hỗn hợp CuO , Mg vào 500 ml dd HBr 0,6M , phản ứng xảy ra vừa đủ a) tính khối lượng mỗi chất và % theo khối lượng mỗi chất trong hỗn hợp ban đầu b) tính thể tích khí bay ra (đktc) c) cần bao nhiêu lít dd HNO3 0,5M để hòa tan hoàn toàn 4,6 gam hỗn hợp trên ? Thể tích khí Nito bay ra là bao nhiêu

Câu 2. Nhà Nguyễn đã hành động gì trong khi Pháp thực hiện chiến lược bóc lột ở Nam Kì và chuẩn bị đánh Bắc Kì lần 1? Tại sao Pháp chiếm 3 tỉnh Nam Kì năm 1867 mà mãi tới năm 1873 mới đánh chiếm Bắc Kì lần 1?

Một hình tròn có diện tích 28,26cm2. Hỏi hình tròn đó có chu vi bằng bao nhiêu?

Mọi người giúp mình bài 1 với,minh sắp nộp rồi

Một vật có khối lượng 5 kg được đặt trên mặt phẳng nghiêng. Lực ma sát giữa vật và mặt phẳng nghiêng bằng 0,2 lần trọng lượng của vật. Chiều dài của mặt phẳng nghiêng là 10 m. Lấy g = 10 m/s2 . Công của lực ma sát khi vật trượt từ đỉnh xuống chân mặt phẳng nghiêng là

I.​Find the word which has a different sound in underlined part. ​1.​A. came​B. lake​C. station​D. start ​2.​A. ancient​B. radio​C. village​D. nature ​3.​A. break​B. head​C. bread​D. heavy ​4.​A. wait​B. said​C. maid​D. sail ​5.​A. train​B. wait​C. said​D. paid ​6.​A. sailing​B. railway​C. brainstorm​D. captain ​7.​A. safety​B. chat​C. taste​D. waste ​8.​A. centre​B. let​C. belt​D. security ​9.​A. safety​B. traffic​C. station​D. plane II.​Choose the correct answer by circling A, B, C or D. ​1.​Linda used to ​​ morning exercise when she got up early. ​A. did​B. does​C. doing​D. do ​2.​My mum ​​ the bus to work every day, but I cycle. ​A. catches​B. drives​C. goes​D. runs ​3.​You should look right and left when you go ​​ the road. ​A. down​B. across​C. up​D. along ​4.​Bus is the main public ​ in Viet Nam. ​A.travel​B. tricycle​C. transport​D. vehicle ​5.​The play was so boring. ​​, An saw it from beginning to end. ​A. Therefore​B. Despite​C. However​D. Although ​6.​She’s sure that they will find the film ​. ​A. entertaining​B. entertain​C. entertainment​D. entertained ​7.​- “Do you like seeing a film?” - “​​” ​A. No, I don’t like it at all​B. Sure. What film shall we see? ​C. Who is in it?​D. I’m sorry, I can’t. ​8.​​ being frightened by the images, Lan still liked the film so much. ​A. In spite​B. Despite​C. Although​D. Nevertheless ​9.​​ is La Tomatina celebrated? - Every August. ​A. Where​B. Why​C. When​D. Which ​10.​My father liked the ​​ of that singer. ​A. perform​B. performer​C. performance​D. performing ​11.​Does your bike ever ​​ down on the way to school? ​A. break​B. take​C. do​D. turn ​12.​I ​ go on foot when I was in primary school. ​A. used to​B. break​C. can​D. may ​13.​Give a ​​ before you turn left or right. ​A. sign​B. turn​C. sound​D. signal ​14.​A lot of dancers go to Rio de Janeiro to ​​ the Carnival. ​A. attend​B. join​C. perform​D. appear ​15.​​ the film was gripping, Tom slept from beginning to end.​ ​A. Therefore​B. Despite​C. However​D. Although III.​Read the text and fill in the blanks with correct words. Use the words in the box. ​in​live​their​with​from ​sleep​are​and​or​gets ​The streets are crowded (1)​​ the traffic. Taxis are bringing tired people (2)​​​ the airport and the train stations to the hotels. They hope to (3)​​ a few hours before their busy day in the big city. Trucks (4)​​ bringing fresh fruits and vegetables into the city. Ships are bringing food (5)​​ fuel to the harbour. ​By seven o’clock (6)​​ the morning, the streets are filled again with people. Millions of people (7)​​ in the big city, and millions of people who work in the big city live in the suburbs, the commuters, are hurrying to get to (8)​​ offices. Everyone is in a hurry. Some stop only to drink a cup of coffee. Others stop to buy the morning paper (9)​​​ to have breakfast. ​The noise of traffic (10)​​ louder. The policemen blow their whistles to stop the traffic or to hurry it along. IV.​Read the text and then choose the best answer A, B, C or D. ​Yesterday, on the way home from school, I saw an accident. A boy was run over by a taxi when he was riding his bicycle. The boy’s leg was broken and it was bleeding badly. Someone there tried to stop the bleeding. They put pressure on it and held it tight. A man used his mobile phone to call the emergency service. Some minutes later, an ambulance arrived and sent the boy to the hospital. Two policemen came to the scene immediately. Some people told the police that the taxi driver was driving at a very high speed when the accident happened. Some others began talking about the traffic accidents these days and blamed the increasing number of accidents on the roads for careless driving and drunk drivers. ​1.​What did the writer see yesterday? ​A. An accident​B. A fire​C. A fighting​D. A crash ​2.​The accident happened between a taxi and ​​.​ ​A. a bus​B. a bicycle​C. a car​D. motorbike ​3.​The boy was sent to the hospital by ​​. ​A. a police​B. a car​C. a passenger​D. an ambulance ​4.​What part of his body was hurt? – His ​​. ​A. arm​B. head​C. leg​D. shoulder ​5.​How was the driver driving when the accident happened? – Very ​​. ​A. fast​B. slowly​C. carefully​D. well V.​Put the means of transport into the correct group. tram(streetcar); lorry; bicycle (bike); motorbike; underground; helicopter; caravan; moped; kayak; train; boat; bus; plane; car; van; coach; ship; taxi Road Air Sea ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ VI.​Put the words and phrases in the right order to make meaningful sentences. ​1.​takes/ art/ half/ gallery/ only/ hour/ to/ an/ the/ It/ to/ get. ​​​ ​2.​mine/ book/ Her/ from/ is/ different. ​​​ ​3.​playing/ young/ brother/ the/ very/ piano/ My/ when/ was/ enjoyed/ he. ​​​ ​4.​are/ I/ as/ as/ not/ thought/ These/ expensive/ clothes. ​​​ ​5.​new/ is/ next/ A/ to be/ going/ school/ built/ year/ here.