cos135*sin210+ctg300*tg315

Cos135*sin210+ctg300*tg315=Cos(90°+45°)*sin(180°+30°)+ctg(270°+30°)*tg(270°+45°)=-sin45°*(-sin30°)-tg30°* (-ctg45°)=√2/2 *1/2 + √3/3 * 1=√2/4+√3/3=(3√2+4√3)/12