2

4

8

16

32

64

128

256

512

1024

2048

4096

8192

1+1=2

2+2=4

4+4=8

8+8=16

16+16=32

64+64=128

128+128=256

512+512=1024

2048+2048=4096

xong

1+1=2

2+2=4

4+4=8

8+8=16

16+16=32

32+32=64

64+64=128

128+128=256

256+256=512

512+512=1024

1024+1024=2048

2048+2048=4096

4096+4096=8192

ahihi đồ ngốc,thật sự thì mình không biết nữa...

*Tham khảo 

\(\dfrac{1}{4}+\dfrac{1}{16}+\dfrac{1}{256}+\dfrac{1}{1024}+\dfrac{1}{4096}\)

\(=\dfrac{1024+256+16+4+1}{4096}=\dfrac{1301}{4096}\)

1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512

A x 2 = 1/4 ( 1/4 + 1/8 + 1/16 + .......... + 1/512 ) - 1/512

A x 2 = 1/4 - A - 1/512

A x 2 - A = 1/4 - 1/512

A = 1/4 - 1/512

A = 127/512

1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512

= 1/2 - 1/4 + 1/4 - 1/8 + ... + 1/256 - 1/512

= 1/2 - 1/512

= 255/512

1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512

= 1/2 - 1/4 + 1/4 - 1/8 + ... + 1/256 - 1/512

= 1/2 - 1/512

= 255/512

1/2 + 1/4+ 1/8+ 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512
= 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 + 1/128 – 1/256 – 1/256 – 1/512
= 1 – 1/512

= 511/512 .

Câu hỏi của Speed of light - Toán lớp 4 - Học toán với OnlineMath

Em tham khảo bài đc OLM k đúng nhé!

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