Is this relation a function?

Both the red and blue line segments stretch from the center of the circle to a point on the circle. the length of the blue segment is 5. how long is the red line segment?

Graph g(x)=2cosx . use 3.14 for π . use the sine tool to graph the function. graph the function by plotting two points. the first point must be on the midline and closest to the origin. the second point must be a maximum or minimum value on the graph closest to the first point.

Iwill give you ! what is the measure of ∠v ?