cos(11π/6)=cos(2π-π/6)=cos(π/6); sin(23π/4)=sin(6π-π/4)=-sin(π/4); sin(5π/3)=sin(2π-π/3)=-sin(π/3); cos(7π/4)=cos(2π-π/4)=cos(π/4); tg(-19π/3)=tg(2π/3-7π)=tg(2π/3). Значения знаешь я надеюсь?
