A regular dodecagon \(P_1 P_2 P_3 \dotsb P_{12}\) is inscribed in a circle with radius 1. Compute \((P_1 P_2)^2 + (P_1 P_3)^2 + \dots + (P_{11} P_{12})^2.\)
(The sum includes all terms of the form \((P_i P_j)^2\) where \(1 \le i < j \le 12\))
+23247 You have the term (P1P2)2
followed by the term (P1P3)2
but you end with the term (P11P12)2.
Is the second term (P1P3)2 or (P2P3)2 ?
