Question

Utilizando a formula da adição de arcos, determine: A) sen 5pi/6 B) cos 5pi/3

Answer 1

$sen(5\pi/6)=sen(\pi-\pi/6)=sen\pi.cos(\pi/6)-sen(\pi/6).cos\pi=1/2 cos(5\pi/3)=cos(2\pi-\pi/3)=cos2\pi.cos(\pi/3)+sen2\pi.cos(\pi/3)=1/2$