Respuesta :

Answer:

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.