TAN(α/2)·(COS(2·pi) + SIN(pi/2 + α)) + SIN(2·α)/COS(pi + α)=
=SIN(α)·(COS(2·pi) + SIN(pi/2 + α))/(COS(α) + 1) + SIN(2·α)/COS(pi + α)=
=SIN(α)·(1 + SIN(pi/2 + α))/(COS(α) + 1) + SIN(2·α)/COS(pi + α)=
=SIN(α)·(1 + COS(α))/(COS(α) + 1) + SIN(2·α)/COS(pi + α)=
=SIN(α) - SIN(2·α)/COS(α)=
=SIN(α) - 2·SIN(α) = - SIN(α)