Question

A=-1/20+-1/30+-1/42+-1/56+-1/72+-1/90

Tìm Am,

Answer 1

A=-1/20+-1/30+-1/42+-1/56+-1/72+-1/90

Tìm Am,

Câu hỏi tương tự Đọc thêmToán lớp 6

Answer 2

\(A=-\left(\frac{1}{4.5}+\frac{1}{5.6}+....+\frac{1}{9.10}\right)\)

\(=-\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-....-\frac{1}{10}\right)=-\left(\frac{1}{4}-\frac{1}{10}\right)=-\frac{3}{20}\)