M = \(\frac{2007}{2008}+\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}\)
So sánh M với 4
Hãy so sánh\(^{\frac{2007}{2008}+\frac{2008}{2009}+\frac{2010}{2011}+\frac{2011}{2008}}\)và 4
Ta có:4=1+1+1+1=\(\frac{2009}{2009}+\frac{2010}{2010}+\frac{2011}{2011}+\frac{2008}{2008}\)
\(\frac{2008}{2009}+\frac{1}{2009}+\frac{2009}{2010}+\frac{1}{2010}+\frac{2010}{2011}+\frac{1}{2011}+\frac{2008}{2008}\)
Xét \(A=\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2008}\)
\(=\frac{2009}{2009}+\frac{2010}{2010}+\frac{2011}{2011}+\frac{2008}{2008}+\frac{1}{2008}+\frac{1}{2008}+\frac{1}{2008}\)
xét \(\frac{1}{2009}< \frac{1}{2008};\frac{1}{2010}< \frac{1}{2008};\frac{1}{2011}< \frac{1}{2008}\)
\(\Rightarrow4< A\)
bạn chắc chắn là đúng chứ
Bạn chắc chắn là bạn làm đúng chứ? Với lại bạn đã từng làm bài này chưa?
So sánh : \(A=\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}vàB=\frac{2008+2009+2010}{2009+2010+2011}\)
Cho A = \(\frac{2000}{2001}+\frac{2001}{2002}+\frac{2002}{2003}+\frac{2003}{2004}+\frac{2005}{2006}+\frac{2006}{2007}+\frac{2007}{2008}+\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}+\frac{2015}{2016}\)
Hãy so sánh tổng các phân số trong A và so sánh với 15.
mỗi số hạng trong biểu thức A đều nhỏ hơn 1 mà có 15 số nên tổng A sẽ nhỏ hơn 15
ta thay tong tren <1+1+1+1+1+1+1+1+1+1+1+1+1+1+1
hay tong tren be hon 15
So sánh : A=\(\frac{2008}{2009}\)+\(\frac{2009}{2010}\)+\(\frac{2010}{2011}\)và B=\(\frac{2008+2009+2010}{2009+2010+2011}\)
\(B=\frac{2008+2009+2010}{2009+2010+2011}\)
\(=\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{2010}{2009+2010+2011}\)
\(< \frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}=A\)
\(B=\frac{2008+2009+2010}{2009+2010+2011}\)
\(=\frac{2008}{2009+2010+2011}=\frac{2009}{2009+2010+2011}=\frac{2010}{2009+2010+2011}\)
\(< A=\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}\)
\(B=\frac{\frac{2008}{2011}+\frac{2009}{2010}+\frac{2010}{2009}+\frac{2011}{2008}+\frac{2012}{503}}{\frac{1}{2008}+\frac{1}{2009}+\frac{1}{2010}+\frac{1}{2011}}\)
\(B=\frac{2009-\frac{2009}{2001}-\frac{2009}{2002}-\frac{2009}{2003}-\frac{2009}{2004}}{2010-\frac{2010}{2001}-\frac{2010}{2002}-\frac{2010}{2003}-\frac{2010}{2004}}:\frac{2009-\frac{2009}{2005}-\frac{2009}{2006}-\frac{2009}{2007}-\frac{2009}{2008}}{2010-\frac{2010}{2005}-\frac{2010}{2006}-\frac{2010}{2007}-\frac{2010}{2008}}\)
minh lam duoc roi . cach viet phan so ban bam vao o mau vang o cuoi trang .cu di con chuot xuong cuoi trang thi thay 1 o vang , vao xem huong dan la biet ngay ma.
So sánh A và B biết \(A=\frac{2006}{2007}-\frac{2007}{2008}+\frac{2008}{2009}-\frac{2009}{2010};B=\frac{1}{2006.2007}-\frac{1}{2008.2009}\)
So sánh \(\frac{2008}{2009}+\frac{2009}{2010}và\frac{2008+2009}{2009+2010}\)
So sánh: \(A=\frac{2008}{2009}\)+ \(\frac{2009}{2010}\) + \(\frac{2010}{2016}\) và \(B=\frac{2008+2009+2010}{2009+2010+2011}\)
Ta có :
\(B=\frac{2008+2009+2010}{2009+2010+2011}=\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{20101}{2009+2010+2011}\)
Ta thấy \(\frac{2008}{2009}>\frac{2008}{2009+2010+2011}\); \(\frac{2009}{2010}>\frac{2009}{2009+2010+2011}\);
\(\frac{2010}{2011}>\frac{2010}{2009+2010+2011}\)
Suy ra : A > B