(a)
[tex] cos(150) [/tex]
we know that
[tex] 150=180-30 [/tex]
[tex] cos(150)=cos(180-30) [/tex]
[tex] cos(150)=-cos(30) [/tex]
now, we can use unit circle
and we get
[tex] cos(150)=-\frac{\sqrt{3}}{2} [/tex]...........Answer
(b)
[tex] sin(150) [/tex]
we know that
[tex] 150=180-30 [/tex]
[tex] sin(150)=sin(180-30) [/tex]
[tex] sin(150)=sin(30) [/tex]
now, we can use unit circle
and we get
[tex] sin(150)=\frac{1}{2} [/tex]...........Answer
