Cho A =2006/2007+2007/2008+2008/2006
So sanh A voi 3
Những câu hỏi liên quan
cho A =2006 / 2007 cong 2007 /2008 cong 2008/ 2009 so sanh voi 3
So sanh A va B biet : A=2006/2007+2007/2008+2008/2009 va B=(2006+2007+2008)/(2007+2008+2009)
A>b
Cách làm: Bạn tách |B ra rồi so sánh với từng ps ở A, sau đó Kết luận
Đúng 0
Bình luận (0)
so sanh A va B
A =\(\frac{2006+2007}{2006\text{x}2007}\)
B =\(\frac{2007+2008}{2007\text{x}2008}\)
\(A=\frac{2006+2007}{2006.2007}=\frac{2006}{2006.2007}+\frac{2007}{2006.2007}=\frac{1}{2007}+\frac{1}{2006}\)
\(B=\frac{2007+2008}{2007.2008}=\frac{2007}{2007.2008}+\frac{2008}{2007.2008}=\frac{1}{2008}+\frac{1}{2007}\)
Vì \(\frac{1}{2007}+\frac{1}{2006}>\frac{1}{2008}+\frac{1}{2007}\)
=> \(A>B\)
Đúng 0
Bình luận (0)
Cho A = 2006/2007 + 2007/2008 + 2008/2006.So sánh với 3
\(A=\frac{2006}{2007}+\frac{2007}{2008}+\frac{2008}{2006}\)
\(A=1-\frac{1}{2007}+1-\frac{1}{2008}+1-\frac{2}{2006}\)
\(A=\left(1+1+1\right)+\left(\frac{1}{2006}-\frac{1}{2007}\right)+\left(\frac{1}{2006}-\frac{1}{2008}\right)\)
\(A=3+\left(\frac{1}{2006}-\frac{1}{2007}\right)+\left(\frac{1}{2006}-\frac{1}{2008}\right)\)
Ta thấy : \(\frac{1}{2006}-\frac{1}{2007}>0\); \(\frac{1}{2006}-\frac{1}{2008}>0\)\(\Rightarrow A>3\)
Đúng 0
Bình luận (0)
cho a = 2006/2007+2007/2008+2008/2006
so sánh a với 3
Cho A = 2006/2007 + 2007/2008 + 2008/2006
So sánh A với 3
Ta có: 3 = 1 + 1 + 1
Ta có: 2006/2007 < 1 ; 2007/2008 < 1 ; 2008/2009 < 1
Nên 2006/2007 + 2007/2008+ 2008/2009 < (1+1+1=3)
Đúng 0
Bình luận (0)
Ta có: \(A=\frac{2006}{2007}+\frac{2007}{2008}+\frac{2008}{2006}\)
\(A=1-\frac{1}{2007}+1-\frac{1}{2008}+1-\frac{2}{2006}\)
\(A=3+\frac{1}{2006}-\frac{1}{2007}+\frac{1}{2006}-\frac{1}{2008}>3\)
Vậy A > 3
Đúng 1
Bình luận (0)
15 tháng 8 2021 lúc 22:45
cho A= 2006/2007 + 2007/2008 + 2008/2006. so sánh A với 3 giúp em với mai em nộp rùi
So sánh 2 biểu thức:
A = 2006/2007 + 2007/2008 + 2008/2009
B = 2006 + 2007 + 2008/2007 + 2008 + 2009
\(A=\frac{2006}{2007}+\frac{2007}{2008}+\frac{2008}{2009}=1-\frac{1}{2007}+1-\frac{1}{2008}+1-\frac{1}{2009}\)
\(=3-\frac{1}{2007}-\frac{1}{2008}-\frac{1}{2009}>1\).
\(B=\frac{2006+2007+2008}{2007+2008+2009}< \frac{2007+2008+2009}{2007+2008+2009}=1\).
Suy ra \(A>B\).
So sánh 2006/2007+2007/2008+2008/2009+2009/2006 voi 4.
Nhanh giúp mk nha!
Ta có:
2006/2007 + 2007/2008 + 2008/2009 + 2009/2006
= 1 - 1/2007 + 1 - 1/2008 + 1 - 1/2009 + 1 + 3/2006
= (1 + 1 + 1 + 1) - (1/2007 + 1/2008 + 1/2009) + 3/2006
= 4 - (1/2007 + 1/2008 + 1/2009) + 3/2006
Vì 1/2007 < 1/2006
1/2008 < 1/2006
1/2009 < 1/2006
=> 1/2007 + 1/2008 + 1/2009 < 3/2006
=> -(1/2007 + 1/2008 + 1/2009) + 3/2006 > 0
=> 4 - (1/2007 + 1/2008 + 1/2009) + 3/2006 > 4 - 0 = 4
=> 2006/2007 + 2007/2008 + 2008/2009 + 2009/2006 > 4
Đúng 0
Bình luận (0)
Ta có:
2006/2007 + 2007/2008 + 2008/2009 + 2009/2006
= 1 - 1/2007 + 1 - 1/2008 + 1 - 1/2009 + 1 + 3/2006
= (1 + 1 + 1 + 1) - (1/2007 + 1/2008 + 1/2009) + 3/2006
= 4 - (1/2007 + 1/2008 + 1/2009) + 3/2006
Vì 1/2007 < 1/2006
1/2008 < 1/2006
1/2009 < 1/2006
=> 1/2007 + 1/2008 + 1/2009 < 3/2006
=> -(1/2007 + 1/2008 + 1/2009) + 3/2006 > 0
=> 4 - (1/2007 + 1/2008 + 1/2009) + 3/2006 > 4 - 0 = 4
=> 2006/2007 + 2007/2008 + 2008/2009 + 2009/2006 > 4
Đúng 0
Bình luận (0)
