Các câu hỏi tương tự
Cho A= \(\frac{1}{1+3}+\frac{1}{1+3+5}+\frac{1}{1+3+5+7}+...+\frac{1}{1+3+5+7+...+2017}\)
Chứng minh A<\(\frac{3}{4}\)
Cho A=\(\frac{1}{1+3}+\frac{1}{1+3+5}+\frac{1}{1+3+5+7}+......+\frac{1}{1+3+.....+2013}\). CMR A<\(\frac{3}{4}\)
Chứng minh rằng: \(\frac{1}{5^3}+\frac{1}{6^3}+\frac{1}{7^3}+...+\frac{1}{2013^3}< \frac{1}{40}\)
Cho \(A=\frac{1}{1+3}+\frac{1}{1+3+5}+\frac{1}{1+3+5+7}+...+\frac{1}{1+3+5+7+...+2013}\)
Cm nó <\(\frac{3}{4}\)Nha mn giúp mk nha còn có mỗi bài này nữa
2,Cho A=9999932015 - 5555572013
chứng minh A chia hết cho 5
3, c/m \(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}<\frac{1}{3}\)
Thực hiện phép tính :
a ) A =\(\frac{2015+2013+2011+2009+...+7+5+3+1}{2015-2013+2011-2009+...+7-5+3-1}\)
b) B = \(\frac{1+\frac{1}{3}+\frac{1}{5}+...+\frac{1}{97}+\frac{1}{99}}{\frac{1}{1.99}+\frac{1}{3.97}+\frac{1}{5.95}+...+\frac{1}{97.3}+\frac{1}{99.1}}\)
chứng minh\(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{2012}-\frac{1}{2013}+\frac{1}{2014}< \frac{2}{5}\)
Cho A=1-\(\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2013}-\frac{1}{2014}\).Chứng minh A>\(\frac{7}{12}\)
chứng minh \(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+....+\frac{1}{2012}-\frac{1}{2013}+\frac{1}{2014}< \frac{2}{5}\)