What is an angle between 0 and 2pi that is coterminal with -9pi/4?

1 Answer
Feb 22, 2018

(7pi)/4

Explanation:

Keep adding a full rotation until you get a coterminal angle in your interval [0, 2pi]

(-9pi)/4+(8pi)/4=(-pi)/4 (Close! Not there yet, though...)

(-pi)/4+(8pi)/4=(7pi)/4 Between [0, 2pi]! Done!