Question

$if \: a1 \: a2.........an \: be \: in \: arithmetic \: progression \: \\ \\ then \: show \: that \\ \\ \frac{1}{a1 \: an} + \frac{1}{a2 \: an - 1} + \frac{1}{a3 \: an - 2} + .......... + \frac{1}{an \: a1} = \frac{2}{a1 + an} ( \frac{1}{a1} + \frac{1}{a2} + ....... + \frac{1}{an} )$
* No Useless Ans. Plz.*

Answer 1

Hope you got the difference