корень(3)*cos(I)-2*cos(I-pi/6) =
корень(3)*cos(I)-2*(cos(I)*cos(Pi/6)+sin(I)*sin(Pi/6)) =
корень(3)*cos(I)-2*(cos(I)*корень(3)/2+sin(I)*1/2) =
корень(3)*cos(I)-(cos(I)*корень(3)+sin(I)*1) =
корень(3)*cos(I)-cos(I)*корень(3)-sin(I) = -sin(I)
корень(3)*cos(I)-2*cos(I-pi/6) =
корень(3)*cos(I)-2*(cos(I)*cos(Pi/6)+sin(I)*sin(Pi/6)) =
корень(3)*cos(I)-2*(cos(I)*корень(3)/2+sin(I)*1/2) =
корень(3)*cos(I)-(cos(I)*корень(3)+sin(I)*1) =
корень(3)*cos(I)-cos(I)*корень(3)-sin(I) = -sin(I)