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

=1/10+1/20+1/40+1/64

=61/320

lấy 1/64 làm mẫu xố chung

1/64+2/64+4/64+8/64+12/64+32/64=59/64

a ) 13/20

B)

C..........................................................

minh dang tính

lấy máy tính mà bấm

sao?

Đặt A=1/2+1/4+...+1/128

=1/2+(1/2)^2+...+(1/2)^7

=>2A=1+1/2+...+(1/2)^6

=>2A-A=1+1/2+...+(1/2)^6-1/2-1/4-...-1/128

=>A=1-1/128=127/128

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

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

S=1-1/64

S=63/64

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

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

2S =1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32

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

S = 1 - 1/64

S = 63/64

Quy đồng các phân số:\(\frac{1}{2}\);\(\frac{1}{4}\);\(\frac{1}{8}\);\(\frac{1}{16}\);\(\frac{1}{32}\);\(\frac{1}{64}\)

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

Kết quả bằng \(\frac{63}{64}\)

                              ____HỌC TỐT____

Câu trả lới được đăng bởi Vật Lý Lương Tử

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

= \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{8}+.....+\frac{1}{32}-\frac{1}{64}\)

= \(1-\frac{1}{64}\)

= \(\frac{63}{64}\)

    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

Chúc bạn học tốt nha!^-^

=63nha ban

     C =           \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) + \(\dfrac{1}{32}\) + \(\dfrac{1}{64}\) + \(\dfrac{1}{128}\)

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

2 \(\times\) C - C =   1 -  \(\dfrac{1}{128}\)

       C       = \(\dfrac{127}{128}\)

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

\(\rightarrow A=\frac{3}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\)

\(\rightarrow A=\frac{7}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\)

\(\rightarrow A=\frac{15}{16}+\frac{1}{32}+\frac{1}{64}\)

\(\rightarrow A=\frac{31}{32}+\frac{1}{64}\)

\(\rightarrow A=\frac{63}{64}\)

\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\Rightarrow64A=32+16+8+4+2+1\Rightarrow64A=63\Rightarrow A=\frac{63}{64}\)