S = 1+3+3^2+3^3+3^4+ ....+3^20
SO SANH S VOI 1/2 . 3 ^ 31
Những câu hỏi liên quan
Cho S=1+3^2+3^4+3^6+.......+3^98+3^100.
So sanh 8S+1 voi 2^152
Tim so du cua S khi chia cho 10.
cau 1 so sanh
3^39vaf 11^21
câu 2 cho S =1+2+262+...+2^9. Hãy so sanh s S voi 5.2^8
câu 3 cm 3^2008 la so co it hon 1005 c/s
Câu 4 so 2^100 co bao nhieu c/s
Cho S= 1/5+2/52+3/53+.....+2015/52015. so sanh voi 1/3
\(5S=1+\frac{2}{5}+\frac{3}{5^2}+...+\frac{2015}{5^{2014}}\Rightarrow4S=1+\frac{1}{5}+\frac{1}{5^2}+...+\frac{1}{5^{2014}}-\frac{2015}{5^{2015}}\)
Đặt B = \(1+\frac{1}{5}+\frac{1}{5^2}+...+\frac{1}{5^{2014}}\)
=> 5B = \(5+1+\frac{1}{5}+\frac{1}{5^2}+...+\frac{1}{5^{2013}}\)
=> 4B = \(5-\frac{1}{5^{2014}}
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So sanh S voi 2 biet: S=1+1/3+1/6+1/10+...+1/45
\(S=1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{1}{45}\)
\(\frac{S}{2}=\frac{1}{2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{9\cdot10}\)
\(\frac{S}{2}=\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{9}-\frac{1}{10}\)
\(\frac{S}{2}=1-\frac{1}{10}\)
\(\frac{S}{2}=\frac{9}{10}\)
\(S=\frac{9}{5}
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Cho S=1+2+2^2+2^3+.....+2^9
So sanh S voi 5.2^8
S = 1 + 2 + 2 ^ 2 + 2 ^ 3 + ... + 2 ^ 9
2S = 2 + 2 ^ 2 + 2 ^ 3 + 2 ^ 4 + .... + 2 ^ 10
2S - S = ( 2 + 2 ^ 2 + 2 ^ 3 + 2 ^ 4 + .... + 2 ^ 10 )
- ( 1 + 2 + 2 ^ 2 + 2 ^ 3 + ... + 2 ^ 9 )
S = 2 ^ 10 - 1
S = 2 ^ 8 . 2 ^ 2 - 1
S = 2 ^ 8 . 4 - 1
S < 2 ^ 8 . 1 < 5 . 2 ^ 8
Vậy S < 5 . 2 ^ 8
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So sanh A voi 1:
A=1/2*2 + 1/3*3 + 1/4*4 + .....+1/2011*2011
So sanh B voi 3/4:
B=1/2*2 + 1/3*3 +1/4*4 + ......+1/2011*2011
cho S=1\3+1\5+1\18+1\30+1\45+1\60+...+1\1485 so sanh S voi 3\5
S=2/3+2/15+2/35+2/63+2/99+...+2/9603 hay so sanh voi 1
1+2+2^2+2^3+......+2^98. hay so sanh S voi 5*2^98
giup voiiiii dang hoc online!!!!!!
A = 1 + 2 + 22 + 23 + .... +298
2A = 2(1 + 2 + 22 + 23 +....+298)
2A = 2 + 22 + 23 + 24 +....+299
2A - A = (2 + 22 + 23 + 24 +.....+ 299) - (1 + 2 + 22 + 23 +.....+298)
A = ( 2 - 2 ) + ( 22 - 22 ) + (23 - 23).....+(298 - 298) + 299 - 1
A = 0 + 0 + 0 +.....+0 + 299 - 1
A = 299 - 1
So sánh :
299 - 1 và 5 . 298
299 - 1 < 5 . 298
( Biết hay sai thì chịu nhe hehe phần so sánh tui
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