а) sin(5π/2 + α) = sin(2π + π/2 + α) = sin(π/2 + α) = cos(α)
б) cos(3π + α) = cos(2π + π + α) = cos(π + α) = -cos(α)
в) sin(7π/2 - α) = sin(3π + π/2 - α) = -sin(π/2 - α) = -cos(α)
а) sin(5π/2 + α) = sin(2π + π/2 + α) = sin(π/2 + α) = cos(α)
б) cos(3π + α) = cos(2π + π + α) = cos(π + α) = -cos(α)
в) sin(7π/2 - α) = sin(3π + π/2 - α) = -sin(π/2 - α) = -cos(α)