K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

a) Ta có: \(\dfrac{1}{1\cdot3}+\dfrac{1}{3\cdot5}+\dfrac{1}{5\cdot7}+...+\dfrac{1}{2007\cdot2009}\)

\(=\dfrac{1}{2}\left(\dfrac{2}{1\cdot3}+\dfrac{2}{3\cdot5}+\dfrac{2}{5\cdot7}+...+\dfrac{2}{2007\cdot2009}\right)\)

\(=\dfrac{1}{2}\left(1-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{2007}-\dfrac{1}{2009}\right)\)

\(=\dfrac{1}{2}\left(1-\dfrac{1}{2009}\right)\)

\(=\dfrac{1}{2}\cdot\dfrac{2008}{2009}=\dfrac{1004}{2009}\)

21 tháng 3 2021

 

 

28 tháng 3 2022

ok man

28 tháng 3 2022

Người nước ngoài à ??

25 tháng 11 2017

 Nội qui tham gia "Giúp tôi giải toán"

1. Không đưa câu hỏi linh tinh lên diễn đàn, chỉ đưa các bài mà mình không giải được hoặc các câu hỏi hay lên diễn đàn;

2. Không trả lời linh tinh, không phù hợp với nội dung câu hỏi trên diễn đàn.

3. Không k "Đúng" vào các câu trả lời linh tinh nhằm gian lận điểm hỏi đáp.

Các bạn vi phạm 3 điều trên sẽ bị giáo viên của Online Math trừ hết điểm hỏi đáp, có thể bị khóa tài khoản hoặc bị cấm vĩnh viễn không đăng nhập vào trang web.

14 tháng 11 2018

if you k me i will make friend with you

14 tháng 11 2018

dịch

Xin chào, bạn có thể kết bạn với tôi không?

Trả lời 

Yes

k tớ nha

Học tốt

20 tháng 2 2019

hello con c*c

Đang giới thiệu kênh youtube

28 tháng 4 2020

dịch nek

Xin chào
Bạn có nghe thấy tôi không, khi tôi hét tên bạn
Xin chào
Bạn có cần tôi không, trước khi tôi biến mất

Đây có phải là nơi tôi gọi là nhà không
Để tìm thấy những gì tôi đã trở thành
Đi dọc theo con đường không rõ
Chúng ta sống, chúng ta yêu, chúng ta nói dối

Trong bóng tối, tôi không cần ánh sáng.
Có một con ma trong tôi
Tất cả thuộc về phía bên kia
Chúng ta sống, chúng ta yêu, chúng ta nói dối

(Chúng ta sống, chúng ta yêu, chúng ta nói dối)

Xin chào
Rất vui được gặp giọng nói của bạn trong đầu tôi
Xin chào
Tôi tin bạn, làm thế nào tôi có thể quên

Đây có phải là nơi tôi gọi là nhà không
Để tìm thấy những gì tôi đã trở thành
Đi dọc theo con đường không rõ
Chúng ta sống, chúng ta yêu, chúng ta nói dối

https://www.youtube.com/watch?v=Y-zZZ7qb5-s&list=TLPQMzAwNDIwMjB_UEHYGR2xeA&index=3

The Spectre - Alan Walker - Kênh âm nhạc chính thức - YouTube

26 tháng 9 2018

You can watch videos on Youtube.vn about making a paper star .

24 tháng 4 2018

It's me

15 tháng 10 2021

là tôi

nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

14 tháng 11 2019

its me :))

III. Complete the dialogue, using the given words        Where     would     when       will          who    o’clock      Mai:Nga:Mai:Nga:Mai:Nga:Mai:Nga:Mai:Nga:Mai Hello. This is 8 873 924.Hello. Is that Mai?Yes. Who is this?It’s me, Nga(1)… Will…..you be free tomorrow afternoon?Yes, I will(2) …Would ……. you like to play tennis?Sure. (3) …where ….. will we play?We’ll play at Lan Anh court.(4) … When……. will we meet?We’ll meet at four (5) …o’clock ……….Ok. I’ll see you tomorrow.     IV. Read...
Đọc tiếp

III. Complete the dialogue, using the given words

        Where     would     when       will          who    o’clock     

Mai:

Nga:

Mai:

Nga:

Mai:

Nga:

Mai:

Nga:

Mai:

Nga:

Mai

 

Hello. This is 8 873 924.

Hello. Is that Mai?

Yes. Who is this?

It’s me, Nga(1)… Will…..you be free tomorrow afternoon?

Yes, I will

(2) …Would ……. you like to play tennis?

Sure. (3) …where ….. will we play?

We’ll play at Lan Anh court.

(4) … When……. will we meet?

We’ll meet at four (5) …o’clock ……….

Ok. I’ll see you tomorrow.

 

 

 

 

 

IV. Read the passage and answer the questions.

          Lien lives in the city with her parents and two brothers. She lives on Nguyen Trai street. Her telephone number is 3720789. On her next birthday, June 21st, Lien will be 14. She will have a small party for her birthday. She will invite some best friends to her house. They will eat cakes and sweets. And they will have a lot of fun. The party will start at five o’clock and finish at nine.

* Choose True(T) or False(F) :

   1. Lien lives with her uncle and aunt.                                             

   2. She is thirteen now.                                                                         

   3. She will invite all of her friends.                                               

   4. She doesn’t have telephone number.                                          

   5. The party will last for two hours.                                              

   6. They will have a lot of fun.                                                       

*Questions:

1. What’s Lien’s address?

……………………………………………………

2. How many people are there in her family?

……………………………………………………

3. Will she have a big party for her birthday?

……………………………………………………

4. Who will she  invite?

……………………………………………………

5. Will they have a lot of fun?

……………………………………………………

6. When is her birthday?

……………………………………………………

V. Fill in the blanks with the words provided

Ngan is from Hue. Her family (1)................ to Dong Nai this year. She studies (2) ................. a bigger school. Her school is large (3) ................ it has a lot of students and teachers. Her old school does not have (4) ................ foreign teachers. Her new school has some foreign teachers. They are from England.

1. A. Leaves           b. moves         c.stays             d. Likes

2. A. In                   b. On                c. With           d. From

3. A. But                 b. Or               c. And             d. With

4. A. Any                 b. Some          c. Not           d. much

VI. Choose the best answers:

1. Her birthday is ……………Friday, August 20th

    a. on

b. in

c. at

d.for

2. This dress is the ………..expensive of the four dresses

      a. best

b. more

c. most

d.much

3. My father take care …………….sick children.

       a. with

b. about

c. in

d.of

4. Would you like …………the movie with me?

       a. see

b. to see

c. seeing

d. sees

5. What …………….. beautiful picture!

       a. the     b. an             c. a                          d. any

6. …………………. take care of sick people.

 a. Doctors    b. Teachers       c. Farmers       d. Journalists

7. I will see you ……….6.45 tomorrow morning.

   a. on        b. to                    c. in                         d. at

8. He will invite some of his friend…. his birthday party.

    a. into    b. to                  c. from                    d. with 

9. Hoa studies ………...… others students in her class.

     a. harder to         b. harder than    c. more hard               d. more hard than

10. The red car is ……………… the blue one.

        a. modern               b. more modern          c. modern than       d. more modern than

11. Minh is …………. boy in my class.

  a. the tallest      b. tallest         c. tall                d. taller

12. We will ……………our old friend next Sunday.

a. to meet

     b. meeting

      c. meet

d.meets

VII. Supply the correct tense form of the verbs

1. Mr Johnson …………… ( be ) my  uncle. He …………………….… ( visit) us next week.

2. He………………… you tomorrow. (call)

3. I ……………14 on my next birthday. (be)

4.  My father never ……….. coffee. (drink)  

5.They ( play) ……………….. volleyball next Sunday.

6. Hoa’s parents (work) ………………… hard from morning till night.

7. Would you like (have) …….. breakfast with eggs?

8. My brother and his friends ( not listen) ………………… to music at present.

VIII. Complete the passage. Then answer

also      empty     near      from    cheapest   expensive       teachers

John Robinson is an English teacher (1) _______ the USA. He (2) ______ English in a high school in Ha Noi. Now he is looking for an apartment (3) ________ the school. There are three (4)__________ apartments. The first one is a big apartment. It’s comfortable, but it’s very (5)_______. The second one is also a lovely apartment, but it’s quite expensive, too. The last one is smaller than the other two, but it’s the (6)  _________  of the three. It has a bright living room, two bedrooms and a large, modern kitchen. Mr. Robinson thinks the third apartment is the most suitable for his family.

Answer the questions

1.What does Mr. Robinson do?

………………………………………………..

2.Where is he from?

……………………………………………………

3. What is he looking for?

…………………………………………………..

4. Which is the cheapest apartment?

……………………………………………..

5. How many apartments are there?

…………………………………………….

6. Which apartment is the smallest?

…………………………………………..

7. What does the third apartment have?

…………………………………………………….

IX/ Matching A and B correctly

A

B

1/ What’s your date of birth?

2/ Would you like to see a movie?

3/ Where does your mother work?

4/ Will you be free next Friday?

5/ Where is she from?

6/ What’s your telephone number?

7/ What’s your middle name?

 

a. She works in the hospital

c. It’s May 6.

d. Sure

e. 840389

f. It’s Thi.

h. London.

g. No, we won’t

1___ 2___ 3____ 4_____ 5_____ 6_____ 7_____

X. Rearrange these sentences.

1. teacher / who / the / to/ talking/ is /?

………………………………………..

2. will/ next/ when/ birthday/ be/ your/?

 …………………………………………………….

 

 

3
11 tháng 11 2021

ai giúp em với ạ

 

17 tháng 3

III. Complete the dialogue, using the given words

Mai: Hello. This is 8 873 924.

Nga: Hello. Is that Mai?

Mai: Yes. Who is this?

Nga: It’s me, Nga. Will you be free tomorrow afternoon?

Mai: Yes, I will.

Nga: Would you like to play tennis?

Mai: Sure. Where will we play?

Nga: We’ll play at Lan Anh court.

Mai: When will we meet?

Nga: We’ll meet at four o’clock.

Mai: Ok. I’ll see you tomorrow.

IV. Read the passage and answer the questions.

True/False:

1. False
2. False
3. False
4. False
5. False
6. True

Answer the questions:

1. Lien's address is Nguyen Trai Street.
2. There are five people in her family (Lien, her parents, and two brothers).
3. No, she will have a small party for her birthday.
4. She will invite some of her best friends to her house.
5. Yes, they will have a lot of fun.
6. Her birthday is on June 21st.

V. Fill in the blanks:

1. B
2. A
3. C
4. C

VI. Choose the best answers:

1. A
2. C
3. D 
4. B. 
5. C. 
6. A. 
7. D
8. B
9. B
10. B
11. A
12. C

VII. Supply the correct tense form of the verbs:

1. is visiting
2. will call
3. will be
4. drinks
5. will play
6. work
7. to have
8. are not listening

VIII. Complete the passage:

1. from
2. teaches
3. near
4. empty
5. expensive
6. cheapest

Answer the questions:

1. He is an English teacher.
2. He is from the USA.
3. He is looking for an apartment near the school.
4. The third apartment is the cheapest.
5. There are three apartments.
6. The third apartment is the smallest.
7. The third apartment has a bright living room, two bedrooms, and a large, modern kitchen.