Question

Aratati ca numarul a este natural,unde a=(2/1•3+2/3•5+2/5•7+...+2/27•29)•29/14

Answer 1

Am atasat rezolvarea!

Answer 2

$\frac{2}{1*3}=1- \frac{1}{3}$
$\frac{2}{3*5}=\frac{1}{3}- \frac{1}{5}$
$\frac{2}{5*7}=\frac{1}{5}- \frac{1}{7}$
.................
$\frac{2}{27*29}=\frac{1}{27}- \frac{1}{29}$
Daca adunam obtinem:
$(1-\frac{1}{29})*\frac{29}{14}=2$