Regular polygon 1

[rsoldo]

Prove that in a regular polygon $A_0A_1A_2...A_{3n-1}$holds equality

$$|A_0A_{n+1}|-|A_0A_{n-1}|=|A_0A_1|.$$

[TOTAL]

$\sin(\pi/3 + t) - \sin(\pi/3 - t) = \sin(t)$