Các câu hỏi tương tự
\(A=\frac{1}{5}-\frac{1}{7}+\frac{1}{17}-\frac{1}{31}+\frac{1}{65}-\frac{1}{127}\)Chứng minh \(A<\frac{1}{10}\)
CMR: \(\frac{1}{5}-\frac{1}{7}+\frac{1}{17}-\frac{1}{31}+\frac{1}{65}-\frac{1}{127}< 10\)
Cho A=\(\frac{1}{5}-\frac{1}{7}+\frac{1}{17}-\frac{1}{31}+\frac{1}{65}-\frac{1}{127}.\)
So sánh A với \(\frac{1}{9}\)
Tìm số nguyên x
a) \(\frac{1}{3}+\frac{-2}{5}+\frac{1}{6}+\frac{-1}{5}\le x< \frac{-3}{4}+\frac{2}{7}+\frac{-1}{4}+\frac{3}{5}+\frac{5}{7}\)
b)\(\frac{5}{17}+\frac{-9}{4}+\frac{-26}{31}+\frac{12}{17}+\frac{-11}{31}< \frac{x}{9}\le\frac{-3}{7}+\frac{7}{15}+\frac{4}{-7}+\frac{8}{15}\)
Chứng minh rằng: Nếu \(\frac{a}{b}=\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+\frac{1}{7}+\frac{1}{8}+\frac{1}{9}+\frac{1}{10}\)
Thì a chia hết cho 13
\(M=\frac{\frac{2}{7}-\frac{2}{13}+\frac{2}{23}}{\frac{-5}{7}+\frac{5}{13}-\frac{5}{23}}+\frac{\frac{1}{17}-\frac{1}{23}+\frac{1}{31}}{\frac{3}{17}-\frac{3}{23}-\frac{3}{31}}\)
16 tính bằng cách hợp lí a) ( frac{1}{4}+ frac{-5}{13}) + ( frac{2}{11}+frac{-8}{13}+frac{3}{4})b) ( frac{21}{31}+frac{-16}{7}) +( frac{44}{53}+ frac{10}{31}) +frac{9}{53}c) frac{-5}{7}+frac{3}{4}+frac{-1}{5}+frac{-2}{7}+frac{1}{4}d) frac{-3}{31}+frac{-6}{17}+frac{1}{25}+frac{-28}{31}+frac{-11}{17}+frac{-1}{5}
Đọc tiếp
16 tính bằng cách hợp lí
a) ( \(\frac{1}{4}\)+ \(\frac{-5}{13}\)) + ( \(\frac{2}{11}+\frac{-8}{13}+\frac{3}{4}\))
b) ( \(\frac{21}{31}+\frac{-16}{7}\)) +( \(\frac{44}{53}\)+ \(\frac{10}{31}\)) +\(\frac{9}{53}\)
c) \(\frac{-5}{7}+\frac{3}{4}+\frac{-1}{5}+\frac{-2}{7}+\frac{1}{4}\)
d) \(\frac{-3}{31}+\frac{-6}{17}+\frac{1}{25}+\frac{-28}{31}+\frac{-11}{17}+\frac{-1}{5}\)
Bài 1:So sánh(bằng 2 cách):
\(A=\frac{10^{11}-1}{10^{12}-1}\)\(B=\frac{10^{10}+1}{10^{11}+1}\)
Bài 2:Chứng minh:
\(\frac{3}{5}< \frac{1}{31}+\frac{1}{32}+\frac{1}{33}+..........+\frac{1}{59}+\frac{1}{60}< \frac{4}{5}\)
Cho A =\(\frac{1}{31}+\frac{1}{32}+\frac{1}{33}+...+\frac{1}{59}+\frac{1}{60}\) Chứng minh rằng A<\(\frac{4}{5}\)