TrigonometrySuperchallengeThe Unit Circle and Circular Functions ShareThe Unit Circle and Circular Functions · Superchallenge problemEvaluate exactly:∑k=011kcoskπ6=0⋅cos0+1⋅cosπ6+2cos2π6+⋯+11cos11π6.\sum_{k=0}^{11} k\cos\frac{k\pi}{6} = 0\cdot\cos0 + 1\cdot\cos\frac{\pi}{6} + 2\cos\frac{2\pi}{6} + \cdots + 11\cos\frac{11\pi}{6}.k=0∑11kcos6kπ=0⋅cos0+1⋅cos6π+2cos62π+⋯+11cos611π.Check Show answer Walk through it step by step Practice more like this Review this concept