Question

Which graphical test is used to find out whether the given graph of equation is a function or not?

• A. Vertical Line Test
• B. Horizontal Line Test
• C. Inclined Line Test
• D. All of the above

Answer 1

The correct option is A Vertical Line Test

Vertical Line Test is used to check whether the given graph represents the function or not.
In this method, we draw the vertical lines and check if that line is cutting the graph at one point or more than that.
For example,

In the above graph, vertical line drawn is cutting the curve at so many points so this curve cannot represent the function. As for one value of $x$, we are getting more than one values of $y$.
Now, let us see another example,

In the above graph, we can see that there is no such vertical line which will cut the curve at more than one points. So, this curve represents function. As in this graph every value of $x$ will have the unique value of $y$.