Given: Angle 0 is in quadrant III and sin0 = -sqrt(6)/4
Prove: cos0 = -sqrt(10)/4
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.