Chứng minh rằng\(\frac{1}{3}\)+ \(\frac{1}{30}\) + \(\frac{1}{32}\) + \(\frac{1}{35}\) + \(\frac{1}{45}\) + \(\frac{1}{47}\) + \(\frac{1}{50}\) < \(\frac{1}{2}\)
Tính A = \(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{49}+\frac{1}{50}}{\frac{1}{49}+\frac{2}{48}+\frac{3}{47}+...+\frac{48}{2}+\frac{49}{1}}\)
Chứng minh rằng:\(\frac{1}{26}+\frac{1}{27}+\frac{1}{28}+....+\frac{1}{49}+\frac{1}{50}=\frac{91}{50}-\frac{97}{49}+\frac{95}{48}-\frac{93}{47}+.....+\frac{7}{4}-\frac{5}{3}+\frac{3}{2}=1\)
CMR
\(\frac{1}{3}+\frac{1}{31}+\frac{1}{35}+\frac{1}{37}+\frac{1}{47}+\frac{1}{53}+\frac{1}{61}< \frac{1}{2}\)
CMR
\(\frac{1}{3}+\frac{1}{31}+\frac{1}{35}+\frac{1}{37}+\frac{1}{47}+\frac{1}{53}+\frac{1}{61}< \frac{1}{2}\)
Tính hợp lý các biểu thức sau: (tức tính nhanh)
\(A=49\frac{8}{23}-\left(5\frac{7}{32}+14\frac{8}{23}\right)\)
\(B=71\frac{38}{45}-\left(43\frac{38}{45}-1\frac{17}{57}\right)\)
\(C=\left(19\frac{5}{8}:\frac{7}{12}-13\frac{1}{4}:\frac{7}{12}\right).\frac{4}{5}\)
\(D=\left[\left(\frac{10}{15}-\frac{2}{3}\right):\frac{1}{7}\right].0,15-\frac{1}{4}\)
\(E=\frac{13}{30}+\frac{28}{45}.2\frac{1}{2}-\left[\left(\frac{1}{2}+\frac{1}{3}\right):\frac{53}{90}\right]:\frac{50}{53}\)
Nhanh nhé, mình cần gấp, 3 người nào nhanh nhất mk tặng cho 5 tik nhé!!!!
CMR
\(\frac{1}{26}+\frac{1}{27}+\frac{1}{28}+.....+\frac{1}{50}=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{49}-\frac{1}{50}\)
CMR:
\(\frac{1}{3} +\frac{1}{31}+\frac{1}{35}+\frac{1}{47}+\frac{1}{53}+\frac{1}{61}<\frac{1}{2}\)
CMR:
\(S=\frac{1}{3}+\frac{1}{31}+\frac{1}{35}+\frac{1}{37}+\frac{1}{47}+\frac{1}{53}+\frac{1}{61}<\frac{1}{2}\)