`(a^2+b^2)(c^2+d^2)=a^2c^2+a^2d^2+b^2c^2+b^2d^2`
`(ac+bd)^2+(ad-bc)^2`
`=a^2c^2+2abcd+b^2d^2+a^2d^2-2abcd+b^2c^2`
`=a^2c^2+b^2d^2+a^2d^2+b^2c^2`
Ta có: `a^2c^2+a^2d^2+b^2c^2+b^2d^2=a^2c^2+b^2d^2+a^2d^2+b^2c^2`
`->đpcm`
Đáp án:
CM :`(a^2+b^2)(c^2+d^2)=(ac+bd)^2+(ad-bc)^2`
Giải thích các bước giải:
`(a^2+b^2)(c^2+d^2)`
`=a^2c^2+a^2d^2+b^2c^2+b^2d^2`
`=(a^2c^2+b^2d^2+2abcd)+(a^2d^2-2abcd+b^2c^2)`
`=(ac+bd)^2+(ad-bc)^2`
R1=R4=R5=4ôm R2=2ôm,R3=8ôm R6=2,4 ôm,Uab=48V,bỏ qua điện trở khóa và điện trở ampe kế,dây nối Tính số chỉ ampe kế 1)k đg 2)k mở
Tổng của ba số bằng 8 tổng của số thứ nhất và số thứ hai bằng 4,7 tổng số hai và số thứ ba bằng 5,5 hãy tìm ba số đó.
Ex 1. Match the common health problem with its definition. 1. flu a. a common illness that affects the nose and/or throat, making you cough, sneeze, etc. 2. allergy b. an abnormal high body temperature 3. cold c. a medical condition that makes you become ill or get a rash when you eat, smell, or touch something. 4. sunburn d. a pain in the middle or inner ear 5. obesity e. the condition of having painful red skin that is caused by staying in the sun for too long. 6. earache f. the pain in a tooth or teeth 7. toothache g. the condition of being fat or overweight 8. fever h. a very bad cold caused by a virus that causes fever, pains and weakness. Ex 2. Fill in the blanks with the health problems in Ex 1. 1. She feels very weak, has a high fever and her muscles hurt. She has_______________. 2. He eats lots of junk food and be overweight. _______________ is his problem. 3. She went outside all day long without wearing a hat. Now her skin turns red and hurts. She has got_____________. 4. I think I’m getting a ____________. I’ve got a sore throat and a runny nose. 5. Mark had lobster for dinner, and now his skin becomes covered with red marks. He says he has a shellfish _______________. 6. If you’ve got ______________, go and see a dentist. 7. His body is too hot and soaked in sweat, but he feels very cold. I think he has a _____________. 8. My sister feels pain in her ear. She has _______________. Ex 3. Complete the sentences with the correct form of the verb “have” or “feel”. Add a or an where necessary. 1. I _____________flu. I ________tired and weak. 2. Jane ___________sick, so she stays at home today. 3. Maybe she __________fever. Her face is red and she tells me that she _______ very hot. 4. I __________terrible headache yesterday, but I _________better now. 5. What’s wrong with Sarah? Does she ___________toothache? 6. “Have you ever __________allergy to seafood?” “Yes, I _________ill when I ate some lobsters two months ago.” 7. My friend________sunburn after a day at the beach. Her skin becomes red and sore. 8. I__________itchy and I __________runny rose. Do I _______cold? Ex 4. Put the words into the correct column. flu, playing sports, cough, walking, sore throat, watching TV, fever, gardening, allergy, swimming, runny nose, doing aerobics, headache, exercising, sneezing, cycling, red skin, relaxing, stomachache, sleeping Illness and symtoms Activities
Câu 1: Phân biệt các chất sau: đâu là đơn chất?, đâu là hợp chất? CO2, CaO, N2, SO3, Fe, Cu(NO3)2, H2, KBr, MgO, Cl2, Ba, PbCl2, Si, NaOH Câu 2: Nêu ý nghĩa công thức hóa học của các phân tử các chất sau, tính phân tử khối của chúng: a) MgCl2 b) Al2(SO4)3 c) Cu(OH)2
Làm dùm e câu exercises 2 với ạ...
giúp mình vs mn vote 5 sao + ctlhn lun ạ
Vẽ con chuột. NL: Lỡ cán vào con chuột chít. Máu me bắn ra cùng nội tạng lòng thòng. Nổi da gà.
Viết một đạn văn ngắn khoảng 7-9 câu có sử dụng câu bị động và câu mở rộng thành phần
Cho mình hỏi là khi Fe + O2 thì trong trường hợp nào ra Fe3O4 hay FeO hay Fe2O3???? Xin cảm ơn.
giúp mik ik mik ko bt làm ae giúp mik
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