#1**+1 **

1) -21pi/8 = -21pi/8 + 4pi = 11pi/8. 11pi/8 is > than pi or 180 degrees, but is < 3pi/2 or 270 degrees, so the terminal ray lies in Quadrant III.

proyaop Feb 21, 2024

#2**+1 **

-5pi/9 = -5pi/9 + 2pi (coterminal) = 13pi/9. 13pi/9 is greater than pi or 180 degrees, but is less than 3pi/2 = 13.5pi/9 or 270 degrees, so this terminal ray also lies in QUadrant III.

proyaop Feb 21, 2024