MathDB

1

Part of 1996 USAMO

Problems(1)

Trig Sum

Source: USAMO 1996

10/22/2005
Prove that the average of the numbers nsin⁡n∘  (n=2,4,6,…,180)n \sin n^{\circ} \; (n = 2,4,6,\ldots,180) is cot⁡1∘\cot 1^{\circ}.
trigonometryratiocomplex numbersgeometric seriesalgebra