The reference angle for -30° can be found by taking the absolute value of the angle and finding the acute angle between 0 and 360 degrees. In this case, the acute angle between 0 and 360 degrees is 30 degrees. So the reference angle α is 30°.
To find sin θ, we can use the relationship between sine and reference angle. Since the sin function is positive in the second quadrant, sin θ is equal to sin α.
sin θ = sin α = sin 30°
Using a calculator, we find that sin 30° is approximately 0.5000.
So sin θ ≈ 0.5000
For each angle θ listed below, find the reference angle α, and then find sin θ. Round sin θ to four decimal places, if necessary.
θ = -30° ? ?
1 answer