To find the exact values of the cosine and sine of the angle 120°, we can use the values of the cosine and sine for the reference angle (60°) and apply the appropriate signs based on the quadrant.
First, let's find the cosine and sine of the reference angle, 60°:
cos(60°) = 1/2
sin(60°) = √3/2
Since the angle 120° is in the second quadrant, the cosine is negative and the sine is positive.
cos(120°) = -1/2
sin(120°) = √3/2
To find the decimal values, we can use a calculator:
cos(120°) ≈ -0.5
sin(120°) ≈ 0.866
Find the exact values of the cosine and sine of the angle. Then find the decimal values.
0 = 120°
1 answer
2 answers