Ta có:1+2+3+...+n=\(\frac{n.\left(n+1\right)}{2}\)
=>B=\(\frac{2.2016}{\frac{2}{2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{2016.2017}}\)
=>B=\(\frac{2016}{\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{2016.2017}}\)
=>B=\(\frac{2016}{\left(\frac{1}{1}-\frac{1}{2}\right)+\left(\frac{1}{2}-\frac{1}{3}\right)+...+\left(\frac{1}{2016}-\frac{1}{2017}\right)}\)
=>B=
Tính nhanh : \(\frac{2017+\frac{1}{2016}+\frac{2}{2015}+\frac{3}{2014}+...+\frac{2015}{2}+\frac{2016}{1}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2015}+\frac{1}{2016}}\)
Tính M , biết :
\(M=1+\frac{1}{2}\times\left(1+2\right)+\frac{1}{3}\times\left(1+2+3\right)+\frac{1}{4}\times\left(1+2+3+4\right)+...+\frac{1}{2016}\times\left(1+2+3+4+...+2015+2016\right).\)
\(A=\left(6:\frac{3}{5}-1\frac{1}{6}x\frac{6}{7}\right):\left(4\frac{1}{5}x\frac{10}{11}+5\frac{2}{11}\right)\)\(B=\left(1-\frac{1}{2}\right)x\left(1-\frac{1}{4}\right)x.......x\left(1-\frac{1}{2015}\right)x\left(1-\frac{1}{2016}\right)\)
\(C=5\frac{9}{10}:\frac{3}{2}-\left(2\frac{1}{3}x4\frac{1}{2}-2x2\frac{1}{3}\right):\frac{7}{4}\)
Cho \(A=\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2016}\)
\(B=\frac{2015}{1}+\frac{2014}{2}+\frac{2013}{3}+...+\frac{2}{2014}\)\(+\frac{1}{2015}\)
Tính \(\frac{A}{B}\)
Mong mọi người giúp đỡ
A =\(\frac{2015+\frac{2014}{2}+\frac{2013}{3}+\frac{2012}{4}+\frac{2011}{5}+.....+\frac{1}{2015}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+......+\frac{1}{2016}}=\)
tìm A
Tính nhanh :
\(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+....+\frac{1}{2016}\)
Tính A=112×113×114....×112016×112017A=1\frac{1}{2}\times1\frac{1}{3}\times1\frac{1}{4}....\times1\frac{1}{2016}\times1\frac{1}{2017}A=121×131×141....×120161×120171
\(\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{2015}-\frac{1}{2016}+\frac{1}{2017}\)
Tính nhanh:\(\frac{\frac{1}{2}}{1+2}+\frac{\frac{1}{2}}{1+2+3}+\frac{\frac{1}{2}}{1+2+3+4}+...+\frac{\frac{1}{2}}{1+2+3+4+...+100}\)
