Question

Вычислите: a) sin 13п/6 б) tg (-11п/6) в)cos п + ctg 4п/3 г)tg п/4 ctg (-п/4) + cos 3п/2 sin п/2 д) sin 405º + cos 225º tg 225º

Answer 1

a) sin 13п/6 =sin(12π/6+π/6)=sin(2π+π/6)=sin π/6=1/2=0.5

б) tg (-11п/6) =-tg(11π/6)=-tg(12π/6-π/6)=-tg(2π-π/6)=tgπ/6=√3/3 

в)cos п + ctg 4п/3 =-1+√3/3

г)tg п/4 ctg (-п/4) + cos 3п/2 sin п/2 =-tg π/4*ctg π/4+0*1=-1

д) sin 405º + cos 225º tg225º = sin(360°+45°)+cos(180°+45°)*tg(180°+45°) =sin45°+(-cos45°)*tg45°=√2/2-√2/2*1=0