cos1755=cos(270+1485)=sin1485=sin(270+1215)=-cos1215=-cos(270+945)=-sin945=
-sin(270+675)=cos675=cos(270+405)=sin405=sin(270+135)=-cos135=-cos(180-45)=cos45=sqrt2/2
cos1755=cos(270+1485)=sin1485=sin(270+1215)=-cos1215=-cos(270+945)=-sin945=
-sin(270+675)=cos675=cos(270+405)=sin405=sin(270+135)=-cos135=-cos(180-45)=cos45=sqrt2/2