Find the value of the sum: sumk=111cosleft(frackpi12right)\\sum_{k=1}^{11} \\cos\\left(\\frac{k\\pi}{12}\\right)sumk=111cosleft(frackpi12right)
000
frac12\\frac{1}{2}frac12
−frac12-\\frac{1}{2}−frac12
111