Вычислите : sin13п/6 , cos 405, tg-11п/6, ctg5п/4/

Question

Вычислите : sin13п/6 , cos 405, tg-11п/6, ctg5п/4/

Answer 1

sin13п/6=sin (2+1/6 )*p=sin p/6=1/2

 cos 405=cos(360+45)=cos 45 =√2 / 2

tg(-11п/6)=tg(p/6)=1/2 : √3/2=1/√3

ctg5п/4=cos5p/4  :  sin5p/4 =-√2/2 : -√2/2=1