$x\to -\infty\Rightarrow \sqrt{x^2}=|x|=-x$
$\lim\limits_{x\to -\infty}\dfrac{ \sqrt{x^2+2x+3}+4x+1}{ \sqrt{4x^2+1}+x-2}$
$=\lim\limits_{x\to -\infty} \dfrac{ -\sqrt{1+\dfrac{2}{x}+\dfrac{3}{x^2}} +4+\dfrac{1}{x} }{ -\sqrt{4+\dfrac{1}{x^2}}+1-\dfrac{2}{x} }$
$=\dfrac{-1+4}{-2+1}$
$=-3$
`lim_{x-> - \infty} (\sqrt{x^2 + 2x + 3} + 4x + 1)/(\sqrt{4x^2 + 1} + x - 2)`
`= lim_{x -> -\ infty} (-\sqrt{1 + 2/x + 3/(x^2)} + 4 + 1/x)/(-\sqrt{4 + 1/(x^2)} + 1 - 2/x)`
`= (4-1)/(1-2)`
`= -3`
Tính giá trị của : N bằng 1.99 cộng 2.98 cộng 3.97 cộng ... cộng 49. 51 cộng 50.50
một ô tô đi từ A đến B với vận tốc 40km/h hết 4h30' . khi ô tô đó đi từ B đến A với vận tốc 50km/h thì hết bao lâu?
ko vẽ hình , mỗi bài chỉ làm câu a thôi nha thank you very múc !!!!
Cho tam giác ABC có AB=6cm, AC=8cm, BC=10cm. Gọi I là giao điểm của 3 đường phân giác, M là trung điểm của cạnh BC. Tia BI cắt AC tại D. CMR: a)Tam giác ABC vuông tại A b) Góc AIC và góc BDC bằng nhau c) 5AD=3DC d) Tam giác BIM vuông tại I
Hãy chọn câu trả lời đúng nhất bằng cách khoanh tròn vào chữ cái đầu tiên (a, b, c, d): 1. After the holiday, they returned to Hanoi ………………bus. a. by b. with c. on d. in 2. Why didn’t you go to school yesterday, Lan?- ……………..I had a bad cold. a. Because b. But c. However d. So 3. Now, Hoa is 40 kilos, by last year she …………………………..35 kilos. a. were b. are c. was d. is 4.She ………………..me of at the railway station yesterday. a. sees b. saw c. seeing d. seen 5. I have a toothache so I’m going to the ………………………. a. nurse b. doctor c. dentist d. teacher 6. …………….is it? – 25000 dong. a. How much b. How old c. How far d. What 7. Remember …………………………….....................the letters for me. a. post b. posted c. posting d. to post 8. How …………………………are you? – I’m 1 meter 69 centimeters. a. heavy b. tall c. long d. old 9. Mr Lam is a good teacher. He teaches very………. a. well b. good c. bad d. badly Đọc hiểu: (2,25 điểm) There (1)............... only one disease called common: The common cold. We call it the common cold (2)............... every year millions of people catch it. Everybody knows (3)...............: a runny nose,a (4)............... fever, coughing and sneezing. It is very unpleasant, but nobody knows a cure. Medicines called cold “cures” don’t call a cold, but they do relieve the symptoms.Whatever you do, your cold will last for a few days and then (5)................ I. Hãy đọc đoạn văn trên và chọn câu trả lời đúng nhất bằng cách bôi đen vào chữ cái đầu tiên (a, b, c, d): 1. a. is b. are c. was d. were 2. a. so b. because c. and d. but 3. a. problems b. things c. symptoms d. activities 4. a. slight b. high c. hot d. common 5. a. cures b. relieves c. appears d. disappears II. Hãy đọc đoạn văn trên, sau đó trả lời câu hỏi: 1. Which disease called common? → ………………………………………………………………………………… 2. Why do we call it the common cold? →………………………………………………………………………………… 3. What are the symptoms? → ………………………………………………………………………………… 4. How long will our cold last? →…………………………………………………………………………………
đốt cháy 10 gam hỗn hợp khí gồm 1 ankan và 1 anken rồi cho sản phẩm đi qua bình đựng nước vôi trong dư thấy có 70 gam kết tủa tạo thành.mặt khác hỗn hợp trên làm mất màu vừa đủ với 100 ml dung dịch Br2 1M. a) Tìm CTPT,CTCT mỗi hidrocacbon. b) Tính % thể tích,%khối lượng mỗi chất trong hỗn hợp. c) trình bày phương pháp hóa học dùng để nhận biết 2 hợp chất trên.
Words form The Best Medicine If you feel stressed or unhappy, nothing, say researchers, is as therapeutic as laughing. A good, (1. HEART) __________ laugh relieves physical tension and stress, leaving your muscles relaxed for up to 45 minutes afterwards. Not only that, laughing triggers the release of endorphins – the body’s ‘feel-good’ chemicals – so it can provide temporary relief from pain. Laughter even increases infection-fighting antibodies, thus improving your resistance to disease. But the best thing about this (2. PRICE) __________ medicine that has so much power to heal and renew is that it’s fun, free, and available in abundance. One of the best ways to increase the amount of time you spend laughing each day is to hang out with entertaining, (3. MISCHIEF) __________ people. These are people who laugh easily – both at themselves and at life’s absurdities. Laughter is contagious, so just hearing others laugh primes your brain and readies you to smile. What’s more, the ‘feel-good’ emotion you get when you laugh will remain with you long after your laughter (4. SIDE) _________. The ability to laugh easily and frequently is a tremendous resource for (5. COME) __________ problems and improving both physical and emotional health. So, go on! Bring your body and mind back into (6. EQUAL) __________ - laugh!
tìm x,y,z thuộc N* để :3^x+2^y=1+2^z
1. They were enraged at the _______ of a policeman accused of murder. (ACQUIT) 2. The individuality, immediacy and _______ in computer games satisfy the needs from these people. (MIMIC) 3. His cartoons _______ lampooned the leading politicians of his time. (MERCY) 4. We are disappointed by her approaching this matter so _______. (AMATEUR) 5. It was sheer _______ to try to drive through the mountains in that thunderstorm. (SANE)
Loga.vn - Cộng Đồng Luyện Thi Trực Tuyến
