Respuesta :

Answer:

-2 sqrt (2) /3

Step-by-step explanation:

sin = -1/3 its in the 3rd quadrant so sin is negative cos is negative

sin^2 O + cos ^2 O = 1

1 - (1/9) = cos^2 O

[tex] \cos( \alpha ) = \frac{ - 2 \sqrt{2} }{3} [/tex]