the cinema is in front of the supermarket

Đặt \(S = \frac{1}{31} + \frac{1}{32} + \frac{1}{33} + . . . + \frac{1}{59} + \frac{1}{60}\)

S có 30 số hạng.Nhóm thành ba nhóm, mỗi nhóm có 10 số hạng

\(S = \left(\right. \frac{1}{31} + \frac{1}{32} + . . . + \frac{1}{40} \left.\right) + \left(\right. \frac{1}{41} + \frac{1}{42} + \frac{1}{43} + . . . + \frac{1}{50} \left.\right) + \left(\right. \frac{1}{51} + \frac{1}{52} + . . . + \frac{1}{60} \left.\right)\)

\(S < \left(\right. \frac{1}{30} + \frac{1}{30} + . . . + \frac{1}{30} \left.\right) + \left(\right. \frac{1}{40} + \frac{1}{40} + . . . + \frac{1}{40} \left.\right) + \left(\right. \frac{1}{50} + \frac{1}{50} + . . . + \frac{1}{50} \left.\right)\)

\(S < \frac{10}{30} + \frac{10}{40} + \frac{10}{50}\)

\(S < \frac{47}{60} < \frac{50}{60} = \frac{5}{6}\)(1)

\(S > \left(\right. \frac{1}{40} + \frac{1}{40} + . . . + \frac{1}{40} \left.\right) + \left(\right. \frac{1}{50} + \frac{1}{50} + \frac{1}{50} + . . . + \frac{1}{50} \left.\right) + \left(\right. \frac{1}{60} + \frac{1}{60} + . . . + \frac{1}{60} \left.\right)\)

\(S > \frac{10}{40} + \frac{10}{50} + \frac{10}{60}\)

\(S > \frac{37}{60} > \frac{35}{60} \left(\right. 2 \left.\right)\)

Từ (1) và (2) => \(\frac{7}{12} < S < \frac{5}{6}\)

hay \(\frac{7}{12} < \frac{1}{31} + \frac{1}{32} + \frac{1}{33} + . . . + \frac{1}{59} + \frac{1}{60} < \frac{5}{6}\)

Tháp Hòa Lai,Tháp Chánh Lộ,Tháp Ponagar,Tháp Poklong Garai, Tháp Po Ro Me

hello everyone, my name is Han . I am 20 years old. My birthday is January 26 , 2004. Bye