Why does cos θ, which normally equals x, become 0 when you evaluate this function

[land_of_ice]

Why does cos θ, which normally equals x, become 0 when you evaluate this function for π/r radians?
(π/r means pi over r radians)
Why does cos θ, which normally equals x, become 0 when you evaluate this function for π/r radians?
It says that the point on the circle for this question is (0,1) so zero = x and y = 1 here.

 

[Mentallic]

For [tex]x=cos\theta[/tex], when x=0, [tex]\theta=\pi/2[/tex] (it can also be [tex]-\pi/2,3\pi/2[/tex] etc. but I don't think you need to deal with that right now).

When you're looking at the circle and any point on the circle (x,y) remember that [tex]cos\theta[/tex] is adjacent/hypotenuse or x/1=x. So since the point on the circle is (0,1), the x value is 0 so [tex]cos(\pi/2)=0[/tex]