Question 19
(GBR 6) The $n$ points $P_1,P_2,\ldots,P_n$ are placed inside or on the boundary of a disk of radius $1$ in such a way that the minimum distance $d_n$ between any two of these points has its largest possible value $D_n$. Calculate $D_n$ for $n$ from $2$ to $7$ and justify your answer.