1
cos²45+sin30-ctg²30=(1/√2)²+1/2-(√3)²=1/2+1/2-3=-2
2
cosπ/3+4sinπ/6-ctg3π/4+tg²2π/3=1/2+4*1/2-(-1)+(√3)²=1/2+2+1+3=6,5
3
3-11cos²x-11sin²x=3-11(cos²x+sin²x)=3-11=-8
4
cos²t+tg²t*cos²t=cos²t(1+tg²t)=cos²t*1/cos²t=1
5
6(tgπ/6-ctg3π/2)*cosπ/6/(2sinπ/2-sin3π/2)=6*(√3/3-2)*√3/2;(2*1-(-1))=
=6*3/6:(2+1)=3/3=1