cho A = \(\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+.......+\frac{1}{99.100}\)
CMR: \(̃̃̃̃\frac{7}{12}< A< \frac{5}{6}\)
Chứng minh:
\(\frac{7}{12}< \frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+...+\frac{1}{99.100}< \frac{5}{6}\)
\(A=\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+...+\frac{1}{99.100}.\)
CM. \(\frac{5}{6}< A< \frac{7}{12}\)
cho A =\(\frac{1}{1.2}+\frac{1}{3.4}+...+\frac{1}{99.100}\)
Chứng minh \(\frac{7}{12}< A< \frac{5}{6}\)
CMR
\(\frac{1.2-1}{2!}+\frac{2.3-1}{3!}+\frac{3.4-1}{4!}+...+\frac{99.100-1}{100!}<2\)
CMR: \(\frac{1}{1.2}+\frac{1}{3.4}\)\(+\frac{1}{5.6}+...+\frac{1}{99.100}=\frac{1}{51}+\frac{1}{52}\)\(+\frac{1}{53}+...+\frac{1}{100}\)
chứng minh rằng:
\(\frac{7}{12}\)<A=\(\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+...+\frac{1}{99.100}
\(CMR:\) \(\frac{1.2-1}{2!}+\frac{2.3-1}{3!}+\frac{3.4-1}{4!}+...+\frac{99.100-1}{100!}\) \(< 2\)
Cho \(A=\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+....\frac{1}{99.100}.\)Chứng minh rằng:
a.\(A=\frac{1}{51}+\frac{1}{52}+\frac{1}{53}+....+\frac{1}{100}.\)
b.\(\frac{7}{12}< A< \frac{5}{6}.\)
