Final answer:
The angle 13π/4 falls in the first quadrant of the unit circle after reducing it by subtracting multiples of 2π.
Step-by-step explanation:
The question you've asked is about determining the quadrant in which the angle 13π/4 lies on the unit circle. To find this, we need to know that each complete revolution around the unit circle is 2π radians. If we reduce 13π/4 by taking away full circles (multiples of 2π), we get π/4, because 13π/4 - 6π/4 (or 3*2π/4) equals π/4, which is in the first quadrant.