A ray from the positive x-axis is rotated −270°
. What is the cosine of the angle formed by this ray?(1 point)
The angle formed by the ray after rotating by -270° can be found by subtracting -270° from 0° (the angle formed by the positive x-axis). Therefore, the angle formed by the ray is 0° - (-270°) = 270°.
The cosine of an angle can be found using the unit circle. Since the ray lies on the positive x-axis after rotating, the cosine of the angle formed by this ray would be equal to the cosine of 270°.
Using the properties of the unit circle, we know that the cosine of 270° is equal to the x-coordinate of the point on the unit circle that is 270° counterclockwise from the positive x-axis. This point lies on the negative y-axis and has an x-coordinate of 0.
Therefore, the cosine of the angle formed by this ray is 0.