\(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{8}+\frac{1}{8}-\frac{1}{16}+\frac{1}{16}-\frac{1}{32}+\frac{1}{32}-\frac{1}{64}+\frac{1}{64}-\frac{1}{128}\)
\(=1-\frac{1}{128}\)
\(=\frac{127}{128}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+.........+\frac{1}{64}-\frac{1}{128}=\frac{1}{1}-\frac{1}{128}=\frac{127}{128}\)
Vào đây: http://olm.vn/hoi-dap/question/152700.html
Và đừng quên tick đúng đấy
1/1-1/2+1/2-1/4....+1/64-1/128=1/1-1/128=127/128
ta có:
1-1/2
1/2-1/4
1/4-1/8
1/8-1/16
1/16-1/32
1/32-1/64
1/64-1/128
biểu thức trên được viết lại là:
=1-1/2+1/2-1/4+1/4-1/16+1/16-1/32+1/32-1/64+1/64-1/128=
=1-1/218
127/128
1/2 x 1/4 x 1/6 x 1/8 x 1/16 x 1/32 x 1/64 x 1/128
=( 1-1/2 ) + ( 1/2 - 1/4 ) + ( 1/4 -1/6 ) + (1/6 - 1/8 ) + ( 1/8 - 1/16 ) + ( 1/16 - 1/32 ) + ( 1/32 - 1/64 ) + ( 1/64 - 1/128 )
= 1- 1/128
= 128/128 - 1/128
=127/128
Chúc các bạn học giỏi nhé !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Ta thấy 1/2=1-1/2
1/2+1/4=3/4=1-1/4
1/2+1/4+1/8=7/8=1-7/8
.............................
Tương tự , ta có :
1/2+1/4+1/8+1/16+1/32+1/64+1/128 = 1-1/128 = 127/128
Đáp số : 127/128
1\2+1\4+1\8+1\16+1\32+1\64+1\128
=(1+1\2+1\4+1\8+1\16+1\32+1\64)-(1\2+1\4+1\8+1\16+1\32+1\64+1\128)
=1-1\128
127\128
Bài làm :
Ta có :
\(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{8}+\frac{1}{8}-\frac{1}{16}+\frac{1}{16}-\frac{1}{32}+\frac{1}{32}-\frac{1}{64}+\frac{1}{64}-\frac{1}{128}\)
\(=1-\frac{1}{128}\)
\(=\frac{127}{128}\)
Chúc bạn học tốt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1/2+1/4/1/8+1/16+1/32+1/64+1/128=64/128+32/28+16/128+8/128+4/128+2/128+1/128= 127/128
127/128 nhé bạn
chúc bạn học tốt .......................................................................................................................