so sanh hai phan so sau: \(\frac{2009}{2010}và\frac{2010}{2011}\)
Những câu hỏi liên quan
So sanh : U = \(\frac{2009^{2005}+1}{2009^{2010}+1}\)va V = \(\frac{2009^{2010}+2}{2009^{2011}+2}\)
17 tháng 8 2018 lúc 19:16
So sánh : \(A=\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}vàB=\frac{2008+2009+2010}{2009+2010+2011}\)
So sánh : A=\(\frac{2008}{2009}\)+\(\frac{2009}{2010}\)+\(\frac{2010}{2011}\)và B=\(\frac{2008+2009+2010}{2009+2010+2011}\)
\(B=\frac{2008+2009+2010}{2009+2010+2011}\)
\(=\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{2010}{2009+2010+2011}\)
\(< \frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}=A\)
\(B=\frac{2008+2009+2010}{2009+2010+2011}\)
\(=\frac{2008}{2009+2010+2011}=\frac{2009}{2009+2010+2011}=\frac{2010}{2009+2010+2011}\)
\(< A=\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}\)
So sánh A và B biết
A=\(\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}\)
B=\(\frac{2009+2010+2011}{2010+2011+2012}\)
A=2.998508205
B=0.999502735
suy ra A>B
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Bài giải
Theo bài ra :
\(A=\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}\)
\(B=\frac{2009+2010+2011}{2010+2011+2012}=\frac{2009}{2010+2011+2012}+\frac{2010}{2010+2011+2012}+\frac{2011}{2010+2011+2012}\)
Ta có :
\(\frac{2009}{2010}>\frac{2009}{2010+2011+2012}\)
\(\frac{2010}{2011}>\frac{2010}{2010+2011+2012}\)
\(\frac{2011}{2012}>\frac{2011}{2010+2011+2012}\)
\(\Rightarrow\text{ }\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}>\frac{2009}{2010+2011+2012}+\frac{2010}{2010+2011+2012}+\frac{2011}{2010+2011+2012}\)
\(\Rightarrow\text{ }A>B\)
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Bài giải
Theo bài ra :
\(A=\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}\)
\(B=\frac{2009+2010+2011}{2010+2011+2012}=\frac{2009}{2010+2011+2012}+\frac{2010}{2010+2011+2012}+\frac{2011}{2010+2011+2012}\)
Ta có :
\(\frac{2009}{2010}>\frac{2009}{2010+2011+2012}\)
\(\frac{2010}{2011}>\frac{2010}{2010+2011+2012}\)
\(\frac{2011}{2012}>\frac{2011}{2010+2011+2012}\)
\(\Rightarrow\text{ }\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}>\frac{2009}{2010+2011+2012}+\frac{2010}{2010+2011+2012}+\frac{2011}{2010+2011+2012}\)
\(\Rightarrow\text{ }A>B\)
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Xem thêm câu trả lời
so sanh
a)-22/45 va -51/101
b)so sanh A=\(\frac{^{2009^{2009}}+1}{^{2009^{20010}}+1}\)va B=\(\frac{2009^{2010}-2}{2009^{2011}-2}\)
câu a ta so sánh số đối của 2 phân số này.nếu ps nào có giá trị tuyệt đối lớn hơn thì nhỏ hơn.
câu b ta nhân cả A và B với 2009 rồi so sánh 2009A với 2009B.ta được A>B
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so sanh hai phan so bang cach hop li nhat ;
2010/2008 và 2011/2010
so sanh
A=2008/2009+2009/2010+2010+2011
B=2008+2009+2010/2009+2010+2011
Dễ thấy:
\(\frac{2008}{2009}>\frac{2008}{2009+2010+2011}\)
\(\frac{2009}{2010}>\frac{2009}{2009+2010+2011}\)
\(\frac{2010}{2011}>\frac{2010}{2009+2010+2011}\)
=>\(\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}>\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{2010}{2009+2010+2011}\)
Hay \(\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}>\frac{2008+2009+2010}{2009+2010+2011}\)
Vậy A > B
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so sanh A va B
A =\(\frac{2009}{2010}\) +\(\frac{2010}{2011}\) B =\(\frac{2009+2010}{2010+2011}\)
Ta có: \(\frac{2009}{2010}>\frac{2009}{2010+2011}\) ; \(\frac{2010}{2011}>\frac{2010}{2011+2010}\)
\(\Rightarrow\frac{2009}{2010}+\frac{2010}{2011}>\frac{2009}{2010+2011}+\frac{2010}{2011+2010}=\frac{2009+2010}{2010+2011}\)
=> A > B
Ta có \(\frac{2009}{2010}>\frac{2009}{2010+2011}\) , \(\frac{2010}{2011}>\frac{2010}{2011+2010}\)
\(\Rightarrow\frac{2009}{2010}+\frac{2010}{2011}>\frac{2009}{2010+2011}+\frac{2010}{2011+2010}=\frac{2009+2010}{2010+2011}\)
\(\Rightarrow A>B\)
so sanh: A=2009^2009+1/2009^2010+1 và B=2009^2010-2/2009^2011-2