2431:11=221 5083:221= 23 => 5083/2431=5083:221/2431:221=23/11

2431:11=221
5083:221= 23
=> 5083/2431=5083:221/2431:221=23/11

`291/891=(97xx3)/(297xx3)=97/297`

`549/1281=(183xx3)/(183xx7)=3/7`

`3672/4284=(6xx612)/(7xx612)=6/7`

`7696/9970=(2xx3848)/(2xx4985)=3848/4985`

`578/3757=(2xx289)/(13xx289)=2/13`

`5083/2431=(23xx221)/(11xx221)=23/11`

\(\dfrac{291}{891}=\dfrac{97}{297};\dfrac{549}{1281}=\dfrac{3}{7}\\ \dfrac{3672}{4284}=\dfrac{6}{7};\dfrac{7976}{9970}=\dfrac{4}{5}\\ \dfrac{578}{3757}=\dfrac{2}{13};\dfrac{5083}{2431}=\dfrac{23}{11}\)

a , tổng các phân số đã cho là : 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 = 79/64 

b, \(\frac{79}{64}\)và \(\frac{2017}{2018}\)=  \(\frac{159422}{129152}\)và \(\frac{129088}{129152}\)= \(\frac{159422}{129152}\)> \(\frac{129088}{129152}\)

=> \(\frac{79}{64}\)> \(\frac{2017}{2018}\) 

a) 1/2 + 1/4 + 1/8 + 1/ 16 + 1/32 + 1/64 

=32/64 + 16/64 + 8/64 + 4/64 + 2/64

=32+16+8+4+2/64 = 66/64= 33/32

b) ta có 33/32 > 1 và 2017/2018<1

nên 33/32 > 2017/2018

Bạn khanh cuong ơi bài này tính đâu đơn giản thế đâu. Cậu làm vắn tắt vậy ai mà hiểu?

\(\dfrac{63}{64}\)

\(\dfrac{32}{64}+\dfrac{16}{64}+\dfrac{8}{64}+\dfrac{4}{64}+\dfrac{2}{64}+\dfrac{1}{64}=\dfrac{32+16+8+4+2+1}{64}=\dfrac{63}{64}\)

 1/2    + 1/4     + 1/8  + 1/16  + 1/32 + 1/64

 = 32/64 + 16/64 + 8/64 + 4/64 + 2/64 + 1/64

 =                         63/64

\(2A=1+\dfrac{1}{2}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}\)

\(2A-A=\left(1+\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{18}+\dfrac{1}{32}\right)-\left(\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}\right)\)

\(A=1-\dfrac{1}{64}\)

\(A=\dfrac{63}{64}\)

giúp em với ạ , em cấn gấp ,  4h em học rồi ạ . Cảm ơn những ai giúp em ạ , em tick luôn ạ

= 63/64 nha

- Tính A x 2

 A x 2  = 1 + 1/2  +1/4  +1/8  +1/16+ 1/32  

- Tính A bằng cách A = A x 2 – A

Vậy  A = 1  + 1/2  +1/4  +1/8  +1/16+ 1/32  -  1/2 - 1/4  - 1/8 -1/16 - 1/32 - 1/64                                        

  A = 1 - 1/64

  A = 63/64

Đặt A=1/2+1/8+1/16+1/32+1/64.Ta có:

A x 2=(1/2+1/8+1/16+1/32+1/64) x 2

A x 2=1+1/2+1/4+1/8+1/16+1/32

A x 2-A=(1+1/2+1/4+1/8+1/16+1/32)-(1/2+1/4+1/8+1/16+1/32+1/64)

A=1-1/64=63/64

Ai đi qua cho mình xin cái k mình k lại cho
 

- Tính A x 2

 A x 2  = 1 + 1/2  +1/4  +1/8  +1/16+ 1/32  

- Tính A bằng cách A = A x 2 – A

Vậy  A = 1  + 1/2  +1/4  +1/8  +1/16+ 1/32  -  1/2 - 1/4  - 1/8 -1/16 - 1/32 - 1/64                                        

  A = 1 - 1/64

  A = 63/64

b: A=1/3+1/9+...+1/3^10

=>3A=1+1/3+...+1/3^9

=>A*2=1-1/3^10=(3^10-1)/3^10

=>A=(3^10-1)/(2*3^10)

c: C=3/2+3/8+3/32+3/128+3/512

=>4C=6+3/2+...+3/128

=>3C=6-3/512

=>C=1023/512

d: A=1/2+...+1/256

=>2A=1+1/2+...+1/128

=>A=1-1/256=255/256

1/2+1/4+1/8+1/16+1/32+1/64

Ta thấy:

1/2=1/1-1/2

1/4=1/2-1/4

1/8=1/4-1/8....

1/64=1/32-1/64

A= 1/1-1/2+1/2-1/4+1/4-1/8+.....+1/32-1/64

A=1 - 1/ 64

A= 63/64

\(\frac{32}{64}+\frac{16}{64}+\frac{8}{64}+\frac{4}{64}+\frac{2}{64}+\frac{1}{64}=\frac{63}{64}\)\(\frac{63}{64}\)

ta thấy:

1/2=1/1-1/2

1/4=1/2-1/4

1/8=1/4-1/8...

1/64=1/32-1/64

A=1/1-1/2+1/2-1/4+1/4-1/8+...+1/32-1/64

A=1/1-1/64

A=63/64