A ray from the positive x-axis is rotated −270° . What is the cosine of the angle formed by this ray?

1 answer

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.