Compute $\\sum_{j=1}^k\\cos^n(j\\pi/k)\\sin(nj\\pi/k)$ – math.stackexchange.com

Compute $\\sum_{j=1}^k\\cos^n(j\\pi/k)\\sin(nj\\pi/k)$ â€" math.stackexchange.com References Compute the series $\\sum_{j=1}^k\\cos^n(j\\pi/k)\\sin(nj\\pi/k)$ Hint: the answer is in fact 0