Question

cos 120=
cos 135=
cos 150=
coa 180=

Answer 1

[tex]\cos(120\textdegree)=-\cos(180\textdegree-120\textdegree)=-\cos(60\textdegree)=-\frac{1}{2}\\ \cos(135\textdegree)=-\cos(180\textdegree-135\textdegree)=-\cos(45\textdegree)=-\frac{\sqrt2}{2}\\ \cos(150\textdegree)=-\cos(180\textdegree-150\textdegree)=-\cos(30\textdegree)=-\frac{\sqrt3}{2}\\ \cos180\textdegree=-1[/tex]