Question

S=\(\frac{2}{5\cdot7}+\frac{2}{7\cdot9}+\frac{2}{9\cdot11}+..........+\frac{2}{93\cdot95}\)

nhanh nha minh dang can gap do

Answer 1

\(S=\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+...+\frac{2}{93.95}\)

\(S=\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+...+\frac{1}{93}-\frac{1}{95}\)

\(S=\frac{1}{5}-\frac{1}{95}\)

\(S=\frac{18}{95}\)

Vậy \(S=\frac{18}{95}\)

Answer 2

Giải 

\(S=\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+...+\frac{1}{93}-\frac{1}{95}\)

\(=\frac{1}{5}-\frac{1}{95}\)

\(=\frac{18}{95}\)

Vậy S=\(\frac{18}{95}\)

Answer 3

may bn giai giup minh bai hinh luon voi

Answer 4

Cô nàng cá tính bắt trước bài của mk

Answer 5

S=\(\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+............+\frac{2}{93.95}\)

S=\(\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}+........+\frac{1}{93.95}\)

S=\(\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+............+\frac{1}{93}-\frac{1}{95}\)

S=\(\frac{1}{5}-\frac{1}{95}=\frac{18}{95}\)

Answer 6

S = \(\frac{2}{5.7}\)+ \(\frac{2}{7.9}\)+ \(\frac{2}{9.11}\)+ .........+ \(\frac{2}{93.95}\)

S = \(\frac{2}{5}\)- \(\frac{1}{7}\)+ \(\frac{1}{7}\)- \(\frac{2}{9}\)+ \(\frac{2}{9}\)- \(\frac{2}{11}\)+ ... + \(\frac{2}{93}\)- \(\frac{2}{95}\)

S=  ( \(\frac{1}{5}\)- \(\frac{1}{95}\)) + (\(\frac{-1}{7}\)+ \(\frac{1}{7}\)) + ( \(\frac{-1}{9}\)+ \(\frac{1}{9}\)) +...+ (\(\frac{-1}{93}\)+ \(\frac{1}{93}\))

S = \(\frac{1}{5}\)- \(\frac{1}{95}\)+0+0+...+0

S = \(\frac{19}{95}\) - \(\frac{1}{95}\)

S = \(\frac{19-1}{95}\)

S = \(\frac{18}{95}\)

Chúc bn học tốt!