Respuesta :

Answer:

Below.

Step-by-step explanation:

The cosine is also negative in Quadrant III.

sin^2 O + cos^2 O = 1

cos^2 O = 1 - sin^2 O

= 1 - (-sqrt(6)/4)^2

= 1 -  (6/16)

=  16/16 - 6 /16

= 10/16

So cos O = -sqrt(10/16)

= -sqrt(10)/4.

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