cos(6α) = cos(6*(3π/5)) = cos(18π/5) = cos(2π + 8π/5) = cos(8π/5) = cos(1.6π) = -0.81
sin(6α) = sin(6*(3π/5)) = sin(18π/5) = sin(2π + 8π/5) = sin(8π/5) = sin(1.6π) = -0.59
Теперь подставляем значения в исходное уравнение:
-0.81 cos(3π/5) + (-0.59) sin(3π/5) = -0.81 cos(π/5) + (-0.59) sin(π/5) = -0.81 0.81 + (-0.59) 0.59 = -0.6561 - 0.3481 = -1.0042
cos(6α) = cos(6*(3π/5)) = cos(18π/5) = cos(2π + 8π/5) = cos(8π/5) = cos(1.6π) = -0.81
sin(6α) = sin(6*(3π/5)) = sin(18π/5) = sin(2π + 8π/5) = sin(8π/5) = sin(1.6π) = -0.59
Теперь подставляем значения в исходное уравнение:
-0.81 cos(3π/5) + (-0.59) sin(3π/5) = -0.81 cos(π/5) + (-0.59) sin(π/5) = -0.81 0.81 + (-0.59) 0.59 = -0.6561 - 0.3481 = -1.0042