Final answer:
To identify functions in a graph, apply the vertical line test. If a vertical line intersects the graph at more than one point, it is not a function.
Step-by-step explanation:
To identify functions in a graph, you need to analyze the graph and see if it passes the vertical line test. The vertical line test states that if a vertical line can intersect the graph at more than one point, then the graph does not represent a function. If the graph passes the vertical line test, then it is a function.
For example, let's consider the graph of a straight line. If the line intersects any vertical line at only one point, then it is a function. However, if the line intersects a vertical line at more than one point, then it is not a function.
Similarly, if you have a curved graph like a parabola or a sine wave, you can use the vertical line test to determine if it represents a function or not.