Đáp án:
${L_1} = \frac{1}{\pi }$
Giải thích các bước giải:
$\begin{array}{l}{L_1} = \mathop {\lim }\limits_{x \to 0} \frac{x}{{\tan \pi x}} = \mathop {\lim }\limits_{x \to 0} \frac{x}{{\frac{{\sin \pi x}}{{\cos \pi x}}}} = \mathop {\lim }\limits_{x \to 0} \frac{{\pi x.\cos \pi x}}{{\pi .\sin \pi x}}\\ = \mathop {\lim }\limits_{x \to 0} \frac{{\pi x}}{{\sin \pi x}}.\mathop {\lim }\limits_{x \to 0} \frac{{\cos \pi x}}{\pi } = \mathop {\lim }\limits_{x \to 0} \frac{{\cos \pi x}}{\pi } = \frac{1}{\pi }.\end{array}$
`L_1 = lim_{x->0} x/(tan(\pix))`
Nếu `lim_{x->a} - f(x) = lim_{x->a} + f(x) = L_1` sau đó `lim_{x->a} f(x) = L_1`
`lim_{x->0} - x/(tan(\pix)) = 1/\pi`
`lim_{x->0} + x/(tan(\pix)) = 1/\pi`
`⇒ L_1 = 1/\pi`
Một hình chữ nhật có diện tích là 1176 cm vuông. Nếu giảm chiều rông đi 4 cm thì được hình chữ nhật mới có diện tích là 1008 cm vuông. Tính chu vi hình chữ nhật ban đầu.
III. Decide which answer (A, B, c or D) best fits each space. Most people enjoy going (1) ............ for their holidays, and having the opportunity to (2) ............ in an interesting city or a seaside (3) ............ If you speak (4) ............ languages, you can make new friends, and (5) ............ home some interesting (6) ............ as presents. But before you can do that, you have to (7) ............ your destination, and that is often a problem! If you fly, then you may find that your flight has been (8) ............ . (9) ............ by train can also be difficult, since trains are often (10) ............ in the summer, and you might have to reserve a (11) ............ in advance. Whichever way you (12) ............, you can have problems with your (13) ............, and it is often difficult to find good (14) ............ Apart from this, you might not be able to afford the (15) ............! 1. A. out B. forward C. abroad D. foreign 2. A. remain B. pass C. spend D. stay 3. A. resort B. post C. too D. one 4. A. strange B. stranger C. foreigner D. foreign 5. A. fetch B. take C. go D. get 6. A. memories B. souvenirs C. memoirs D. recollections 7. A. reach B. arrive C. go D. travel 8. A. waited B. reversed C. delayed D. booked 9. A. Journeys B. Travels C. Voyages D. passes 10. A. filling B. occupied C. overdone D. crowded 11. A. post B. chair C. seat D. position 12. A. voyage B. travel C. trip D. tour 13. A. baggage B. luggage C. goods D. sacks 14. A. staying B. homes C. lodges D. accommodation 15. A. fare B. fair C. far D. fur
các từ "đầu","ruột" trong hai từ "hai đầu" và "đường ruột ốc" là: A.Nghĩa gốc B.Nghĩa chuyển C.Vừa Nghĩa gốc vừa nghĩa chuyển D.Không có nghĩa nào
II. Complete each part sentence (a-j) with one of the endings (1-10) and make a compound word. a. I sent my friend a post ............ b. I fastened my seat ............ c. We stayed on a small camp ............ d. I always forget my guide ............ e. Don't forget to take your swim ............ f. If you lose your pass ............ g. We stayed in a quiet guest ............ h. The train time ............ a. I used to like going to the sea ............ i. Nowadays I'm afraid that hitch ............ 1. suit with you to the beach. 2. table turned out to be wrong. 3. belt, and waited for takeoff. 4. port, you must tell the police 5. hiking can be dangerous. 6. side when I was little. 7. card of the town where I stay 8. book when I visit old cities. 9. house down by the river. 10. site just outside the town.
I. Underline the correct answer. A. As a teenager, I (1) used / would to do things that my parents (2) weren’t approving / didn’t approve of. They (3) were always complaining / had always been complaining about my actions. When they (4) lectured / had lectured me, I had (5) covered / would cover my ears and ignore them. Now, I’m experiencing the same thing with my own children! B. Today I (6) had had / had an awful day. I (7) arrived / was arriving at the office, (8) sat / was sitting down at my desk and suddenly (9) had discovered / discovered that I (10) had lost / lost a document on my computer because of a virus. I (11) worked / had been working on it for the past two days. As if that (12) wasn’t / wasn’t being enough, a colleague (13) would get / was getting on my nerves. While I (14) had been trying / was trying to remain calm, she (15) had laughed / was laughing at me.
Cho hình tam giác MNP,trên NP lấy điểm K sao cho NK = 1/2 NP,nối MK [như hình vẽ]. Tính diện tích hình tam giác MNP , biết diện tích hình tam giác MNK bằng 54cm2
biêt được các khái niệm : kiểu gen , kiểu hình , cặp tính trạng tương phản và giống thuần chủng , lai phân tích giải giúp em vs đang gấp ạ :))
nêu ý nghĩa tượng trưng của thủy tinh
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