Question

   

tính  A=\(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{92.95}+\frac{1}{95.95}\)

Answer 1

Đề sai rồi! Đề đúng nè: A = 1/2.5 + 1/5.8 +.......+ 1/92.95 + 1/95.98

Bài làm : A =.............Ghi lại đề

3A  = 3/2.5 + 3/5.8 +........+ 3/95.98

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

3A = 1/2 - 1/98

3A = 48/98

A = 16/98 = 8/49

Answer 2

3A=\(\frac{3}{2.5}+\frac{3}{5.8}+...+\frac{3}{95.98}\)

3A= \(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{95}-\frac{1}{98}\)

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

3A=\(\frac{49}{98}-\frac{1}{98}\)

3A=\(\frac{24}{49}\)

A=\(\frac{8}{49}\) 

Answer 3

SAI DE