Find one positive and one negative angle coterminal with an angle of 9pi/6

21pi/6 and - 3pi/6.

Step-by-step explanation:

We add or subtract 2pi from the angle:

9pi/6 + 2 pi

= 9pi/6 + 12pi/6

= 21pi/6 is the positive angle

9pi/6 - 2pi

= 9pi/6 - 12pi/6

= - 3pi/6.