Chứng minh rằng: \(\frac{1}{5}+\frac{1}{14}+\frac{1}{28}+\frac{1}{44}+\frac{1}{61}+\frac{1}{85}+\frac{1}{97}\) < \(\frac{1}{2}\)
Chứng minh:
\(\frac{1}{5}+\frac{1}{14}+\frac{1}{28}+\frac{1}{44}+\frac{1}{61}+\frac{1}{85}+\frac{1}{97}< \frac{1}{22}\)
Chứng minh rằng:
\(\frac{1}{5}+\frac{1}{14}+\frac{1}{28}+\frac{1}{44}+\frac{1}{61}+\frac{1}{85}+\frac{1}{91}<\frac{1}{2}\)
chứng minh
\(\frac{1}{5}\)+\(\frac{1}{14}\)+\(\frac{1}{28}\)+\(\frac{1}{44}\)+\(\frac{1}{61}\)+\(\frac{1}{85}\)+\(\frac{1}{97}\)<\(\frac{1}{2}\)
chung minh rang:\(\frac{1}{5}+\frac{1}{14}+\frac{1}{31}+\frac{1}{44}+\frac{1}{61}+\frac{1}{84}+\frac{1}{96}< \frac{1}{2}\)
Chứng minh rằng \(S=\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}
Chứng minh rằng:\(\frac{1}{26}+\frac{1}{27}+\frac{1}{28}+....+\frac{1}{49}+\frac{1}{50}=\frac{91}{50}-\frac{97}{49}+\frac{95}{48}-\frac{93}{47}+.....+\frac{7}{4}-\frac{5}{3}+\frac{3}{2}=1\)
chứng minh \(\frac{1}{5}+\frac{1}{13}+\frac{1}{25}+\frac{1}{41}+\frac{1}{61}+\frac{1}{85}+\frac{1}{113}<\frac{1}{2}\)
Chứng minh:
c.\(\frac{11}{15}< \frac{1}{21}+\frac{1}{22}+\frac{1}{23}+...+\frac{1}{59}+\frac{1}{60}< \frac{3}{2}\)
b.\(\frac{1}{5}+\frac{1}{13}+\frac{1}{25}+\frac{1}{41}+\frac{1}{61}+\frac{1}{85}+\frac{1}{113}< \frac{1}{2}\)
a.\(\frac{1}{4}+\frac{1}{16}+\frac{1}{36}+\frac{1}{64}+\frac{1}{100}+\frac{1}{144}+\frac{1}{196}< \frac{1}{2}\)