Các câu hỏi tương tự
Chứng minh rằng \(\frac{1}{3}+\frac{1}{7}+\frac{1}{13}+\frac{1}{21}+\frac{1}{31}+\frac{1}{43}+\frac{1}{57}+\frac{1}{73}+\frac{1}{91}< 1\)
Lấy \(\varphi=1,618\); tính \(\frac{\varphi}{1\cdot2}+\frac{\varphi}{2\cdot3}+\frac{\varphi}{3\cdot5}+\frac{\varphi}{5\cdot8}+\frac{\varphi}{8\cdot13}+\frac{\varphi}{13\cdot21}+\frac{\varphi}{21\cdot34}+\frac{\varphi}{34\cdot55}+\frac{\varphi}{55\cdot89}+\frac{\varphi}{89\cdot144}+...\)
So sánh \(A\)với\(13\),biết rằng:
\(A=\frac{13}{15}+\frac{7}{5}+\frac{3}{4}+\frac{1}{5}+\frac{1}{7}+\frac{19}{20}+\frac{5}{4}+\frac{1}{3}+\frac{1}{6}+\frac{1}{13}+\frac{17}{23}+\frac{9}{8}+\frac{2}{5}+\frac{1}{7}+\frac{1}{25}+\frac{3}{2}+\frac{1}{8}+\frac{1}{19}+\frac{1}{9}+\frac{1}{97}\)
Chứng minh rằng : \(\frac{1}{3}+\frac{1}{7}+\frac{1}{13}+\frac{1}{21}+\frac{1}{31}+\frac{4}{43}+\frac{1}{57}+\frac{1}{73}+\frac{1}{91}<1\)
( lời giải chi tiết nha , mình đang cần gấp )
\(\frac{10+\frac{9}{2}+\frac{8}{3}+\frac{7}{4}+ \frac{6}{5}+\frac{5}{6}+\frac{4}{7}+\frac{3}{8}+\frac{2}{9}+\frac{1}{10}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{10}+\frac{1}{11}}\)
\(y=\frac{4\frac{6}{11}x11\frac{8}{9}+4\frac{12}{13}:3\frac{2}{5}}{123\frac{34}{45}:21\frac{1}{8}}\)
\(S=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH \(\frac{2}{5}< S< \frac{7}{8}\)
\(A=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH :
\(\frac{2}{5}< A< \frac{8}{9}\)
\(A=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH \(\frac{2}{5}< S< \frac{7}{8}\)