\(\dfrac{x+1}{2014}+\dfrac{x+2}{2013}=...+\dfrac{x+1007}{1008}=\dfrac{x+1008}{1007}+\dfrac{x+1009}{1006}+...+\dfrac{x+2014}{1}\)
BT1: Tính
5) \(\dfrac{1}{1+\dfrac{2009}{2011}+\dfrac{2009}{2010}}+\dfrac{1}{1+\dfrac{2010}{2009}+\dfrac{2010}{2011}}+\dfrac{1}{1+\dfrac{2011}{2009}+\dfrac{2011}{2010}}\)
Cho \(A=\dfrac{2}{3^2}+\dfrac{2}{5^2}+\dfrac{2}{7^2}+.............+\dfrac{2}{2007^2}\)
Chứng minh \(A< \dfrac{1003}{2008}\)
Help me!!!!!!!!!!
So sánh P và Q
\(P=\dfrac{2010}{2011}+\dfrac{2010}{2012}+\dfrac{2012}{2013};Q=\dfrac{2010+2011+2012}{2011+2012+2013}\)
Tính tổng : \(\dfrac{1}{5}+\dfrac{1}{20}+\dfrac{1}{44}+\dfrac{1}{77}+\dfrac{1}{119}+\dfrac{1}{170}+\dfrac{1}{230}+\dfrac{1}{299}\)
Tính:
D =\(\dfrac{\dfrac{2010}{1}+\dfrac{2009}{2}+\dfrac{2008}{3}+...+\dfrac{1}{2010}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{2011}}\)
cho M =1+3+32+33+......+3118+3119
N=\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+......+\(\dfrac{1}{2009^2}\)+\(\dfrac{1}{2010^2}\)
CHỨNG TỎ RẰNG
a)M\(⋮\)13
b)N<1
BT1: Tính nhanh:
4) (\(1-\dfrac{1}{2010}\)) . ( \(1-\dfrac{2}{2010}\)) . (\(1-\dfrac{3}{2010}\)) ...... ( \(1-\dfrac{2011}{2010}\))
rút gọn p/s:
a,\(\dfrac{6.9-2.17}{63.3-119}\)
b,\(\dfrac{3.13-13.18}{15.40-80}\)
c, \(\dfrac{25.13}{26.35}\)