Tính : 2007 ^ 1 ^ 2*3*4*...*2005
Những câu hỏi liên quan
tính M :N biết: N=1/2+1/3+1/4+......+1/2007+1/2008 và M= 2007/1+2006/2+2005/3+......+2/2006+1/2007
\(\frac{M}{N}=\frac{\frac{1}{2007}+\frac{2}{2006}+......+\frac{2006}{2}+\frac{2007}{1}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+.......+\frac{1}{2006}+\frac{1}{2007}}\)
\(\frac{M}{N}=\frac{\frac{1}{2007}+1+\frac{2}{2006}+1+.......+\frac{2007}{1}+1+\frac{2008}{2008}-2008}{\frac{1}{2008}+\frac{1}{2007}+\frac{1}{2006}+.....+\frac{1}{2}}\)
\(\frac{M}{N}=\frac{\frac{2008}{2007}+\frac{2008}{2006}+....+\frac{2008}{1}+\frac{2008}{2008}-2008}{\frac{1}{2008}+........+\frac{1}{2}}\)
đến đây là ra rùi ha
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ê tớ chẳng hiểu gì cả
cậu làm tắt à
please cậu giúp tớ cả bài đi mà
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Giúp mình 2 bài này với
Bài 1: Tính Q= 1*3/3*5+2*4/5*7+3*5/7*9+...+(n-1)(n+1)/(2n-1)(2n+1)+....+1002*1004/2005*2007
Bài 2: tính R= 22/1*3+32/2*4+42/3*5+...+20062/2005*2007
Cho: A= 1/2 + 1/3 + 1/4+ ... +1/2008
B= 2007/1 + 2006/2 + 2005/3 +... +2/2006 + 1/2007
Tính B/A
chịuiuiuiuiuiuiuiuiuiuiuiu
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tính nhanh
A=2008+2007/2+2006/3+2005/4+…..+2/2007+1/2008
1/2+1/3+1/4+1/5+…..+1/2007+1/2008
A=2008+2007/2+2006/3+2005/4+...+2/2007+1/2008
1/2+1/3+1/4+1/5+...+1/2007+1/2008
=(1+2007/2)+(1+2006/3)+(1+2005/4)+...+(1+2/2007)+(1+1/2008)
1/2+1/3+1/4+...+1/2008
=2009(1/2+1/3+1/4+...+1/2008)
1/2+1/3+1/4+..+1/2008
=2009
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2008+2007/2+2006/3+2005/4+2005/5+........................3/2006+2/2007+1/2008
1/2+1/3+1/4+1/5+....................+1/2009
2008-1/2008=2007/2008
1/2-1/2009=2007/2009
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2008+2007/2+2006/3+2005/4+2005/5+........................3/2006+2/2007+1/2008
1/2+1/3+1/4+1/5+....................+1/2009
Tính A/ B biết
A= 2008+ 2007/2 + 2006/3 + 2005/4+....+ 2/2007+ 1/2008 ; B = 1/2+1/3+1/4+1/5+....1/2008+1/2009
1 Tính
A (1-1/2) * (1-1/3 ) * (1-1/4 ) * .....*(1-1/19)* ( 1-1/20)
B 3/2 * 4/3 * 6/5* ......* 2006/2005 * 2007/2006 * 2008/2007
\(A=\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot......\cdot\left(1-\frac{1}{20}\right)\)
\(A=\frac{1}{2}\cdot\frac{2}{3}\cdot......\cdot\frac{19}{20}\)
\(A=\frac{1.2.3.....19}{2.3........20}\)
\(A=\frac{1}{20}\)
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(2008+2007/2+2006/3+2005/4+....+2/2007+1/2008) / (1/2+1/3+1/4+...+1/2009)
Xét tử
2008+2007/2+2006/3+2005/4+ ... +2/2007+1/2008
=(1+1+1+...+1)+2007/2+2006/3+2005/4+ ... +2/2007+1/2008
= 1+ (2007/2)+1+(2006/3)+1+(2005/4)+1+ ... + (2/2007)+1+(1/2008)+1
=2009/2009+2009/2+2009/3+2009/4+ ... + 2009/2007 + 2009/2008
=2009.(1/2+1/3+1/4+ ... + 1/2007+1/2008+1/2009)
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Ta có tử số bằng: 2008+2007/2+2006/3+2005/4+…..+2/2007+1/2008
(Phân tích 2008 thành 2008 con số 1 rồi đưa vào các nhóm)
= (1 + 2007/2) + (1 + 2006/3) + (1 + 2005/4) +... + (1 + 2/2007) + ( 1 + 1/2008) + (1)
= 2009/2 + 2009/3 + 2009//4 + ……. + 2009/2007 + 2009/2008 + 2009/2009
= 2009 x (1/2 + 1/3 + 1/4 + ... + 1/2007 + 1/2008 + 1/2009)
Mẫu số: 1/2 + 1/3 + 1/4 + ... + 1/2007 + 1/2008 + 1/2009
Vậy A = 2009