Question

the value of 2/1x3 + 2/3x5+2/5x7+...+2/77x79 is

Answer 1

\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+....+\frac{2}{77.79}\)

=\(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+....+\frac{1}{77}-\frac{1}{79}\)

=\(1-\frac{1}{79}\)

=\(\frac{78}{79}\)

Answer 2

Giá trị của 2 / 1x3 + 2 / 3x5 + 2 / 5x7 + ... + 2 / 77x79 là..........