a) cos 5π/12 + cos π/12 = cos(2π/3) + cos(π/6) = -1/2 + √3/2 = √3/2 - 1/2
б) cos 7π/12 - cos π/12 = cos(7π/12) - cos(π/12) = -√3/2 - √3/2 = -√3
a) cos 5π/12 + cos π/12 = cos(2π/3) + cos(π/6) = -1/2 + √3/2 = √3/2 - 1/2
б) cos 7π/12 - cos π/12 = cos(7π/12) - cos(π/12) = -√3/2 - √3/2 = -√3