Question

Tìm A

A= 5²/1.6 + 5²/6.11 +5²/11.16  +5² /16.21  + 5² /21.26

Answer 1

\(\frac{5^2}{1.6}+\frac{5^2}{6.11}+\frac{5^2}{11.16}+\frac{5^2}{16.21}+\frac{5^2}{21.26}\)

= \(5\left(\frac{5}{1.6}+\frac{5}{6.11}+\frac{5}{11.16}+\frac{5}{16.21}+\frac{5}{21.26}\right)\)

=\(5\left(1-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+\frac{1}{21}-\frac{1}{26}\right)\)=\(5\left(1-\frac{1}{26}\right)\)

=\(5.\frac{25}{26}\)

=\(\frac{125}{26}\)