Question

1)cos 5п/6? 2)sin(-7п/4) 3)tg11п/3 4)ctg(-3,5п

Answer 1

cos5π/6=cos(π-π/6)=-cosπ/6=-√3/2
sin(-7π/4)=-sin(2π-π/4)=sinπ/4=√2/2
tg11π/3=tg(4π-π/3)=-tgπ/3=-√3
ctg(-3,5π)=-ctg(4π-0,5π)=ctg0,5π=0