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PrecalculusSuperchallengePolar Coordinates and Complex Numbers

Polar Coordinates and Complex Numbers · Superchallenge problem

Evaluate ∑k=010(10k)cos⁡(60k)∘\displaystyle\sum_{k=0}^{10}\binom{10}{k}\cos(60k)^\circ, that is, (100)cos⁡0∘+(101)cos⁡60∘+(102)cos⁡120∘+⋯+(1010)cos⁡600∘\binom{10}{0}\cos0^\circ+\binom{10}{1}\cos60^\circ+\binom{10}{2}\cos120^\circ+\cdots+\binom{10}{10}\cos600^\circ.