# Trig functions of Central Directed Angles

Use the slider to change the value of r. What do you notice about the ratio , the x-coordinate of the point P divided by the length of r?

Use the slider for or the animation button in the bottom left hand corner to move explore angles in quadrants outside of quadrant one.

Do you think the reference angle for is the same as the reference angle for matching terminal ray that appears in quadrant one?

What do you notice about the relationship between the coordinates of the point P and the coordinates of the matching point in the first quadrant?