tinh tong sau 1/2 + 1/4 + 1/6 + 1/8 + 1/16+ ..........+ 1/2048
tinh tong sau 1/2 + 1/4 + 1/6 + 1/8 + 1/16+ ..........+ 1/2048
ai trả lời nhanh nhất mimh cho 2 cái like
tính tổng sau:
1/2 + 1/4 + 1/8 + 1/16 ..... + 1/2048
2047/2048 nha mình làm ở violympic cấp tỉnh rồi
1/2+1/4+1/6+1/8+1/16+ +1/2048 hãy tính tổng ?
tinh cac tong sau bang cach thuan tiện nhat P=1\2+1\4+1\8+1\16+...+1\256
P=1/2+1/4+...+1/256
2P=2.(1/2+1/4+...+1/256)
2P-P=(1+1/2+...+1/128)-(1/2+1/4+...+1/256)
P= 1- 1/256
P= 255/256
chắc chắn đúng.
nhớ **** cho mình nha
tính nhanh ;
1234.5678.(630 -315) :1996
319.45+ 55.319 /1995.1996 -1991.1995
1988.1996+1997.11+1985 /1997.1996-1995.1996
(1+2+4+8+.....+512) .(101.102-101.101-50-51) /2+4+6+8+16+....+1024+2048
(1+2+4+8+....+512).(135135.246-246246.135)/2+4+8+16+....+1024+2048
1/2+1/4+1/8+1/16+..........................+1/2048
Gọi biểu thức trên là A Ta có :
A = \(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+......+\frac{1}{2048}\)
=> A : 2 = \(\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+....+\frac{1}{2048}+\frac{1}{4096}\)
=> \(\frac{1}{2}\)A = \(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+......+\frac{1}{2048}\)- \(\frac{1}{4}-\frac{1}{8}-\frac{1}{16}-\frac{1}{32}-......-\frac{1}{2048}-\frac{1}{4096}\)
=> A : 2 = \(\frac{1}{2}-\frac{1}{4096}\)
=> A : 2 = \(\frac{2047}{4096}\)
=> A = \(\frac{2047.2}{4096}\)
=> A = \(\frac{4094}{4096}\)
Đặt A = 1/2 + 1/4 + 1/8 + 1/16 + ... + 1/2048
2A = 1 + 1/2 + 1/4 + 1/8 + ... + 1/1024
2A - A = (1 + 1/2 + 1/4 + 1/8 + ... + 1/1024) - (1/2 + 1/4 + 1/8 + 1/16 + ... + 1/2048)
A = 1 - 1/2048
A = 2047/2048
Đặt A = 1/2 + 1/4 + 1/8 + 1/16 + ... + 1/2048
2A = 1 + 1/2 + 1/4 + 1/8 + ... + 1/1024
2A - A = (1 + 1/2 + 1/4 + 1/8 + ... + 1/1024) - (1/2 + 1/4 + 1/8 + 1/16 + ... + 1/2048)
A = 1 - 1/2048
A = 2047/2048
Đã xog, bây h chỉ cần k
Tim cach tinh nhanh tong sau ma khong quy dong mau so
A=1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
A=\(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{256}\)
A=\(\left(1-\frac{1}{2}\right)+\left(\frac{1}{2}-\frac{1}{4}\right)+\left(\frac{1}{4}-\frac{1}{8}\right)+...+\left(\frac{1}{128}-\frac{1}{256}\right)\)
A=\(1-\frac{1}{256}\)
A=\(\frac{255}{256}\)
A = 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256
2A = 1/2 x 2 + 1/4 x 2 + 1/8 x 2 + 1/16 x 2 +1/32 x 2 + 1/64 x 1/128 + 1/256 x 2
2A = 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
2A - A = ( 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 ) - ( 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 )
A = 1 - 1/256
A = 255/256
1/2+1/4+1/8+1/16+...................................+1/1024+1/2048
A = 1/2+1/4+...+1/2048
2A= 1+ 1/2+ 1/4+...+1/1024
2A-A= ( 1+ 1/2+...+1/1024 ) - (1/2+1/4+...+2048)
A= 1- 1/2048
A= 2047/2048
1/2+1/4+1/8+1/16+..........................+1/2048+1/4096
bn tham khảo tại link này nhé :
https://olm.vn/hoi-dap/question/656309.html
https://olm.vn/hoi-dap/question/656309.html