Školjka

%V0 Dokažite identitet $$\frac{a_1}{a_2\left(a_1+a_2\right)} + \frac{a_2}{a_3\left(a_2+a_3\right)} + \cdots + \frac{a_n}{a_1\left(a_n+a_1\right)} = \frac{a_2}{a_1\left(a_1+a_2\right)} + \frac{a_3}{a_2\left(a_2+a_3\right)} + \cdots + \frac{a_1}{a_n\left(a_n+a_1\right)} \text{.}$$