The answers are : A and C
Seeing where the x and y diffreant on the line :)
60 because all of the sides are equal
<span>arccos (cos pi/2)=?
</span>cos pi/2=0, arccos (0)=?, we know that cos pi/2=0, so cos^-1 (o)= Pi/2, but cos^-1 (o)=arccos (0), so arccos (cos pi/2)=Pi/2
