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17 tháng 12 2016

a) Ta có: \(f\left(\frac{1}{3}\right)=\frac{1}{3}+\frac{1^2}{3^2}+\frac{1^3}{3^3}+....+\frac{1^{2016}}{3^{2016}}\)

\(\Rightarrow3.f\left(\frac{1}{3}\right)=1+\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{2015}}\)

\(\Rightarrow3.f\left(\frac{1}{3}\right)-f\left(\frac{1}{3}\right)=\left(1+\frac{1}{3}+...+\frac{1}{3^{2015}}\right)\)\(-\left(\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{2016}}\right)\)

\(\Rightarrow2.f\left(\frac{1}{3}\right)=1-\frac{1}{3^{2016}}\)

\(\Rightarrow f\left(\frac{1}{3}\right)=\frac{1-\frac{1}{3^{2016}}}{2}\)

17 tháng 12 2016

Bài này  bạn phải vẽ hình để xác định C1 và D1 nằm ở đâu??  a b c c C D Where is C1 và D1

14 tháng 7 2021

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17 tháng 12 2016

3,2x + (-1,2)x + 2,7 = -4,9

=> x(-1,2+3,2)=(-4,9)-2,7

=> 2x=(-7,6)

=> x=(-7,6):2

=> x=(-3,8)

I. Give the correct form of the words given to complete the sentences  1. The Temple of Literature is considered one of the most important  .......... sites of Viet Nam.      HISTORY  2. The school is quite normal, but its .......... are really beutiful.    SURROUND  3. The university grows and receives ............ from the society.     RECOGNISE  4. Is Hung Kings' Temple a ............ place in Viet Nam?            CULTURE  5. The university was a great  ........... and it became famous all...
Đọc tiếp

I. Give the correct form of the words given to complete the sentences

  1. The Temple of Literature is considered one of the most important  .......... sites of Viet Nam.      HISTORY

  2. The school is quite normal, but its .......... are really beutiful.    SURROUND

  3. The university grows and receives ............ from the society.     RECOGNISE

  4. Is Hung Kings' Temple a ............ place in Viet Nam?            CULTURE

  5. The university was a great  ........... and it became famous all over the world.       SUCCEED

  6. The students were ........... prepared for the final exam.      CARE

  7. Was the ............ of the first Doctors' Stone Tablet ordered by King Le Thanh Tong?         ERECT

  8. Many students and teachers have contributed for the ........... of the school.       DEVELOP

  9. Thong Nhat Palace is a tourist ........... in Ho Chi Minh City.               ATTRACT

 10. Many ...........  and scholars discussed about the change of the curricula.         EDUCATE

 

II. Choose the answer A, B, C or D to finish the sentences

  1. Khue Van Pavillion is ........ as the symbol of Ha Noi City

       A. considered        B. regarded      C. surrounded        D. expected

  2. Tom doesn't know why  many students pay a  ........  to the Temple of Literature before their exams.

       A. walk          B. trip        C. visit     D. holiday

 3. The laboratory is ......... to the main building.

      A. next          B. near          C. in front           D. between

 4. You'd better ...... an umbrella because it's rainy.

      A. taking        B. to take         C. will take          D. take

 5. The University of Oxford ........ among the top five university in the world.  

      A. ranks        B. is ranked        C. is ranking         D. being ranked

 6. I think the University of Cambridge is the second ............ university in the United Kingdom.

      A. old            B. older           C. oldest           D. elder

 7. We ......... to Professor Marshall about the research topic two days ago. 

      A. spoke          B. were speaking             C. have spoken             D. were spoken

 8. The Imperial Academy was constructed  ............. Emperor Ly Nhan Tong. 

      A. within              B. under           C. behind             D. above

 9. The institution ............ of many classrooms and libraries for students.

     A. is consisted              B. has been consisted           C. consists             D. is consist

 10. Active voice: Harvard University has awarded Nam a scholarship.

      Passive voice: Nam ............ a scholarship by Harvard University.

      A. has is awarded         B. has was awarded           C. has be awarded            D. has been awarded

 

III. Put the following sentences into the passive voice

   1. People invented the wheel thousands of years ago.

    ............................................................................. .

   2. Are they building a statue of Chu Van An?

    ..............................................................................?

   3. Do four busy streets surround the Temple of Literature?

    ..............................................................................? 

   4. They will not provide pencils at the test, so please bring your own.

    ......................................................................................... .

   5. Mr.Binh hasn't taught us since the last semester. 

    ..................................................................................... .

   6. A students teacher is doing that experiment.

    ............................................................................ .

   7. Did you buy this dictionary two weeks ago?

    .......................................................................... ? 

   8. Alan's knowledge about science and technology doesn't impress me.

   .............................................................................. .

   9. They are going to build a new school here next year. 

    .............................................................................. . 

    10. I have used this computer for two years.

     ......................................................................... .

 

IV. Read the following passage and choose the best answer for each blank.

   Almost all people have a fear of examinations. Examinations, ........ (1), are a past of our lives and all schools in Viet Nam have examinations.

   Examinations were first ........(2) in China about three thousand years ago. Scholars had to memorise long passage taken from several books. Those who did well in the examination ........(3) to enter the government service.

   Nowadays, the main ........(4) of examinations is to test how well a person understands the subjects which have been taught. They are also used to find how well students perform ......(5) pressure.

      1. A. however            B. although            C. therefore             D. also

      2. A. played               B. made                C. held                    D. gained

      3. A. allowed             B. were allowed        C. have allowed             D. allowing

      4. A. part                     B. idea                C. contect                      D. purpose

      5. A. under               B. above                   C. within               D. inside

0
17 tháng 12 2016

5^x + 5^x + 1 = 150

=> 5^x . ( 1 + 5 ) = 150

=> 5^x . 6 = 150

=> 5^X = 150 : 6

=> 5^x = 25

=> 5^x = 5^2

=> x = 2

17 tháng 12 2016

\(5^x+5^{x+1}=150\)

\(\Rightarrow5^x+5^x.5=150\)

\(\Rightarrow5^x\left(5+1\right)=150\)

\(\Rightarrow5^x=150:6\)

\(\Rightarrow5^x=25\)

\(\Rightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)

17 tháng 12 2016

rất tieecs mình chưa học tam giác cân

17 tháng 12 2016

bạn nào giải giúp mik bài này đúng mik k:

Cho a,b thuộc ,biết a^2+ab+b^2 chia hết cho 10

CMR: a^3-b^3 chia hết cho 1000

17 tháng 12 2016

Em đem từng điểm thế vào. Nếu 2 bên ra kết quả giống nhau là thuộc, không giống là không thuộc. Bài này dài nên chị hướng dẫn em làm thôi nhé

9 tháng 11 2021

A=1 đoán :))