To solve this, we can look at the unit circle (see attached photo), We know:
(0,1) = π/2
(-1, 0) = π
(0, -1) = 3π/2
(1, 0) = 0
Across the circle, we know that π/3 is between 0 and π/2. Therefore, as the unit circle line between that is positive in the x direction (cos), we can say that cos(π/3) is positive
