Question

In the following figure, select whether the green and red graphics are functions or not

A. both are functions

B. green is function, red is not function

C. green is not a function, red is a function

D. none is function​

Answer 1

C. green is not a function, red is a function

Explanation:

A curve does not describe a functional relationship if a vertical line crosses it in more than one place. Clearly the y-axis crosses the green curve in 2 places, so it is NOT a function.

There is a very steep section at x=10 on the red curve. It we assume it is simply "very steep" and not "vertical", then the red curve IS a function. If you assume that short section is vertical, then the red curve is not a function, either. My choice is to go with "very steep," not "vertical."

My conclusion is that green is not a function; red is a function.