A ray from the positive x-axis is rotated −270° . What is the cosine of the angle formed by this ray?
To find the cosine of the angle formed by the ray, we first need to determine the angle formed by the ray after rotation.
The ray is rotated −270°, which means it is rotated in the clockwise direction by an angle of 270°.
Since the initial ray is along the positive x-axis, rotating it by 270° in the clockwise direction will result in a ray that is parallel to the negative y-axis.
The angle formed by the ray and the negative y-axis is 90°.
Therefore, the cosine of this angle is the cosine of 90°, which is 0.
So, the cosine of the angle formed by this ray is 0.