Các câu hỏi tương tự
CMR: \(A=\frac{9}{5^2}\)+\(\frac{9}{11^2}+\frac{9}{17^2}+...+\frac{9}{305^2}<\frac{3}{4}\)
Cho A = \(\frac{1}{5^2}+\frac{1}{11^2}+\frac{1}{17^2}+.......+\frac{1}{409^2}\)
CMR A<\(\frac{1}{12}\)
1. Tính
a) \(\frac{-17}{30}-\frac{11}{-15}+\frac{-7}{12}\)
b) \(\frac{-5}{9}+\frac{5}{9}:\left(1\frac{2}{3}-2\frac{1}{12}\right)\)
a) \(\frac{-10}{13}+\frac{8}{17}-\frac{3}{13}+\frac{12}{17}-\frac{11}{20}\)
b) \(\frac{3}{4}+\frac{-5}{6}-\frac{11}{-12}\)
c) \(\left[13.\frac{4}{9}+2.\frac{1}{9}\right]-3.\frac{4}{9}\)
Cho C=\(\frac{1}{5^2}+\frac{1}{9^2}+...+\frac{1}{409^2}\)
CMR C<\(\frac{1}{12}\)
a )-\(-\frac{17}{30}-\frac{11}{-15}+-\frac{7}{12}\)
b ) \(-\frac{5}{9}+\frac{5}{9}:\left(1\frac{2}{3}-2\frac{1}{12}\right)\)
c ) \(-\frac{7}{25}.\frac{11}{13}+-\frac{7}{25}.\frac{2}{13}-\frac{18}{25}\)
1) Cho \(A=\frac{9}{10!}+\frac{9}{11!}+\frac{9}{12!}+...+\frac{9}{1000!}.CMR:A< \frac{1}{9!}\)
2) \(CMR:\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{100^2}< \frac{1}{2}\)
Ai giúp mk sẽ đc thưởng 3 tick , phải ghi chép đầy đủ nha
Tìm x:
\(\frac{\left(13\frac{2}{9}-15\frac{2}{3}\right)\cdot\left(30^2-5^4\right)}{\left(18\frac{3}{7}-17\frac{1}{4}\right)\cdot\left(25-12\cdot5^2\right)}\cdot x=\frac{\frac{2}{11}+\frac{3}{13}+\frac{4}{15}+\frac{5}{17}}{4\frac{1}{11}+\frac{5}{13}+\frac{9}{15}+\frac{13}{17}}\)
cho A = \(\frac{9}{5^2}+\frac{9}{11^2}+\frac{9}{17^2}+....+\frac{9}{305^2}\)chứng minh A <\(\frac{3}{4}\)