Скоротить в тригонометрической форме (не числовой) cos(2п/3)*cos(п/4)-xcos(2п/3)*sin(п/4)+xsin(2п/3)*cos(п/4)-sin(2п/3)*sin(п/4)

[cos2π/3cosπ/4+sin2π/3sinπ/4]+x[sin2π/3cosππ/4-cos2π/3sinπ/4]=
=cos(2π/3-π/4)+xsin(2π/3-π/4)=cos5π/4+xsin5π/4=
=-cosπ/4-xsinπ/4=-√2/2-x*√2/2=-√2/2(1+x)