1
a)4sin330=4sin30=4*1/2=2
b)2cosπ/4cosπ/6/(cos(π/3-π/12))=2cosπ/4cosπ/6/(cosπ/4)=
=2cosπ/6=2*√3/2=√3
2
a)2cos²a*sina/cosa=2cosasina=sin2a
b)(sin9acos3a-cos9asin3a)/sin3acos3a -2=2sin(9a-3a)/sin6a - 2=
=2sin6a/sin6a -2=2-2=0
5
2sin50cos50-sin80=sin100-sin80=2sin10cos90=2sin10*0=0