Em hãy nêu biểu hiện về tác dụng sinh lí học và tác dụng nhiệt của dòng điện. Lấy VD trong cuộc sống

Bài 1 : Cho ΔABC cân tại A . Kẻ AH ⊥ BC tại H a) C/m Δ ABH = Δ ACH , từ đó suy ra H là trung điểm của BC b) Cho AB = 10cm , BC = 12cm . Tính AH c) Kẻ HI ⊥ AB , HK ⊥ AC. C/m Δ AIK cân d) Qua B kẻ đường thẳng song song với AC cắt HK tại E . C/m IE ⊥ IK Bài 2 : Cho ∠xAy nhọn , phân giác AD . Kẻ DB ⊥ Ax , DH ⊥ Ay ( B thuộc Ax , H thuộc Ay ) a) C/m Δ ABD = Δ AHD b) C/m AD là trung trực BH c) Cho BD cắt Ay tại C , HD cắt Ax tại I . C/m Δ DIC cân d) C/m BH // IC e) C/m AD ⊥ IC f) Thêm điều kiện của ∠xAy để B là trung điểm của AI

Bài 2: Cho ΔABC. Một đường thẳng song song với BC cắt cạnh AB tại D và cắt cạnh AC ở E sao cho thỏa mãn hệ thức DC ²=BC.DE. a) So sánh các tam giác DEC và DBC. b) Suy ra cách dựng đoạn DE. c) Chứng minh: AD ²=AC.AE và AC ²=AB.AD 1)Cho ΔABC có 3 góc nhọn và 3 dường cao AD,BE,CF cắt nhau tại H. Chứng minh: a) BD.BC=BF.BA b) Góc CDE= góc BAC c) DH là tia phân giác của góc FDE.

the cost of living in vietnam is low compared......Singapore. A.as B.with C.of D.than

III.Circle the letter A, B, C, or D to indicate the correct answer to each of the following questions. 12. Our school football team____________ the match with Nguyen Du school last Saturday. A. wins B. won C. wi D. to win 13. The food is very ……………………………….….. A. long B. delicious C. noisy D. historic 14. Where do you …………………………….. fishing ? A. play B. do C. go D. have 15. You should wear ………..to protect your eyes from the chlorine in the water. A. glasses B. goggle C. goggles D. Sunglasses 16. Hai can ……………………………..…… boxing well. A. do B. play C. go D. have 17. The …………………... tells people what is happening in Viet Nam and the rest of the world. A. national B. cartoon C. game show D. 7 o’clock news 18. Big Ben is the most famous tower in ……………………………………………………….. A. Viet Nam B. England C. America D. Australia 19. Who …………..the first person in the room yesterday? A. is B. was C. were D. Has been 20. Last summer, I ……………sailing with my father on the river near my house. A. go B. gone C. went D. Have gone

bài thuyết trình về Giờ trái đất và hành động của học sinh tham gia Giờ trái đất năm 2021

giải thích hiện tượng đun nước không đổ đầy siêu

People often talk about English as a global language or lingua franca. With more than 350 million people around the world speaking English as a first language and more than 430 million speaking it as a second language, there are English speakers in most countries around the world. Why is English so popular, though? And why has it become a global language? People often call English the international language of business, and it’s increasingly true as international trade expands every year, bringing new countries into contact. Many of the best MBA programs are taught in English, so speaking it well can put you in a position to get the best training and credentials. Most multinational companies require a certain degree of English proficiency from potential employees so in order to get a position with a top company, more and people are learning English. If your ambitions lie in science or medicine, you can’t neglect English either. Much of the technical terminology is based on English words, and if you want to learn about the latest developments and discoveries from around the world, you’ll read about them in journals and research reports published in English, no matter whether the scientists who wrote them are from China or Norway. If you want a career in travel, English is absolutely essential. As the international language of aviation, pilots and cabin crew all need to speak English. Even if you’re not up in the air, speaking English accurately will ensure you are able to communicate with clients and suppliers all over the world. So, what’s stopping you from learning this global language? With all the English resources available on the internet and so many other English speakers around the world to practice with, there’s never been a better time to start learning English. Pick up a book, learn a few words, or even start a course today and take your first steps towards becoming one of nearly 800 million English speakers in the world. Answer the question 1. Where is English spoken? 2. What qualification is required to work in most multinational companies? 3. Why is English important if you want to pursue a medical career? Giúp mình với, mình cần gấp, please!

tại sao giữa đg ray lại có khe hở

Rewrite the statements below 1 My mother (tell)........ me an interesting story. Last year , she (can take)...........in a competiton at her office 2.They (never eat ).......................Mexican food. Now , they (try)..........to eat. 3.Hoa (walk).................in the rain many time. She loves it ! 4.We (never see)...............such a big flower.We (not visit)................Nha Trang yet 5.I (read)..........................that novel three time.He (never meet)...............her before