Question

Tính: A = \(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+....+\frac{1}{92.95}+\frac{1}{95.98}\)

Answer 1

A = \(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{92.95}+\frac{1}{95.98}\)

A = \(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{95}-\frac{1}{98}\)

A = \(\frac{1}{2}-\frac{1}{98}\)

A = \(\frac{24}{49}\)

Vậy A = \(\frac{24}{49}\)

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#Sunrise

Answer 2

\(A=\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{92.95}+\frac{1}{95.98}\)

\(=\frac{1}{3}\left(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{92.95}+\frac{3}{95.98}\right)\)

\(=\frac{1}{3}\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{92}-\frac{1}{95}+\frac{1}{95}-\frac{1}{98}\right)\)

\(=\frac{1}{3}\left(\frac{1}{2}-\frac{1}{98}\right)\)

\(=\frac{1}{3}.\frac{24}{49}=\frac{8}{49}\)

Answer 3

A=1/3.(1/2-1/5 + 1/5 - 1/8 +......+1/92 - 1/95 + 1/95 - 1/98)

A=1/3.(1/2 - 1/98)

A=1/3. 48/98

A=48/294

Theo mk thì như vậy

Chúc bạn hok tốt ^O^

Answer 4

A = \(\frac{1}{2}\)- \(\frac{1}{5}\)+ \(\frac{1}{5}\)- \(\frac{1}{8}\)+ \(\frac{1}{8}\)- \(\frac{1}{11}\)+ ..... + \(\frac{1}{92}\)- \(\frac{1}{95}\)+ \(\frac{1}{95}\)-\(\frac{1}{98}\)

    = \(\frac{1}{2}\)- \(\frac{1}{98}\)

=> A = \(\frac{48}{98}\)

Nhớ **** cho mk nha, ngồi nguyên buổi để lm mấy cái phân số đó

Answer 5

A = \(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+..+\frac{1}{92.95}+\frac{1}{95.98}\)

   = \(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-..-\frac{1}{95}+\)\(\frac{1}{95}-\frac{1}{98}\)

   = \(\frac{1}{2}-\frac{1}{98}\)

   = \(\frac{1}{2}+\frac{-1}{98}\)

   = \(\frac{49}{98}+\frac{-1}{98}\)

   = \(\frac{48}{98}=\frac{24}{49}\)

Chúc bạn học tốt

 k mik nha, mik đang cần điểm hỏi đáp ♥♥