Question

Oblicz
sin 225° , cos 19/6π tg-300° , ctg 11/3π

Answer 1

Sin225=sin(180+45)=-sin45= -√2/2
cos(19/6π)=cos(2π+7/6π)=cos7/6π=cos(π+π/6)= -cosπ/6= -√3/2
tg(-300)= -tg300=-tg(360-60)=-[-tg60)]=tg60=√3

cos19/6πtg(-300)=(-√3/2)*√3= -3/2= -1,5

ctg11/3π=ctg(2π+5/3π)=ctg5/3π=ctg(2π-π/3)= -ctgπ/3= -√3/3