\(2009-\frac{2010}{3}-\frac{2010}{6}-\frac{2010}{15}-...-\frac{2010}{45}\)
\(=2009-2010.\left(\frac{1}{3}+\frac{1}{6}+\frac{1}{15}+...+\frac{1}{45}\right)\)
\(=2009-2010.\frac{1}{2}.\left(\frac{1}{6}+\frac{1}{12}+\frac{1}{30}+...+\frac{1}{90}\right)\)
Có vấn đề chỗ 2010/15 bạn xem lại
Cho \(\frac{2010\cdot c-2011\cdot b}{2009}=\frac{2011\cdot a-2009\cdot c}{2010}=\frac{2009\cdot b-2010\cdot c}{2011}\)
C/m \(\frac{a}{2009}=\frac{b}{2010}=\frac{c}{2011}\)
\(A=\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\cdot\cdot\cdot+\frac{1}{2011}+\frac{1}{2012}\)
\(B=\frac{2011}{1}+\frac{2010}{2}+\frac{2009}{3}+\cdot\cdot\cdot\frac{2}{2010}+\frac{1}{2011}\)
Tính \(\frac{B}{A}\)
(-2)\(\left(-1\frac{1}{2}\right)\cdot\left(-1\frac{1}{3}\right)\cdot...\cdot\left(-1\frac{1}{2010}\right)\)
tính lẹ
\(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\cdot\cdot\cdot+\frac{1}{2012}+\frac{1}{2013}}{\frac{2012}{1}+\frac{2011}{2}+\frac{2010}{3}+\frac{1}{2012}}\)
a,\(\left(x-1\right)\cdot\left(x+2\right)>0\)
b,\(\left(\frac{1}{2}-x\right)\cdot\left(2x-1\right)< 0\)
c,\(\frac{x-1}{2007}+\frac{x-2}{2008}=\frac{x-3}{2009}+\frac{x-4}{2010}\)
d,\(\left(2x-1\right)\cdot\left(2-x\right)>0\)
Tìm x
bạn nào bít thì giúp mình nha!!!
CMR\(\frac{a+2009}{a-2009}=\frac{b+2010}{b-2010}thi\frac{a}{2009}=\frac{b}{2010}\)
Cho A = \(\frac{2010}{2009^2+1}\)+\(\frac{2010}{2009^2+2}\)+\(\frac{2010}{2009^2+3}\)+.........+\(\frac{2010}{2009^2+2009}\)
CMR : A không phải là số nguyên dương
tính tổng sau :\(c=\frac{\frac{1}{2008}-\frac{1}{2009}-\frac{1}{2010}}{\frac{5}{2008}-\frac{5}{2009}-\frac{5}{2010}}+\)\(\frac{\frac{2}{2007}-\frac{2}{2008}-\frac{2}{2009}}{\frac{3}{2007}-\frac{3}{2008}-\frac{3}{2009}}\)
Tính \(A=-\frac{1}{2010}-\frac{1}{2010\times2009}-\frac{1}{2009\times2008}-.....-\frac{1}{3\times2}-\frac{1}{2\times1}\)
