This is a free lesson from our course in Algebra I
In this lesson you'll learn how to determine if a graph is a function or not. You'll also learn about the Vertical Line test, which is used to determine whether
a relation is a function or not. In this test, if you can draw a vertical line on
the graph of a relation such that it intersects the graph at more than one points, then the relation
is not a function, otherwise it is a function.E.g. Determine whether the relation represented in the graph is a function. Identify the domain and range, if it is a function.
(Continued from above) Solution:
•
a relation is a function if every input has exactly one output.
• in the plot, for each xcoordinate, there is only one ycoordinate.
• so, the relation is a function.
• the domain is 1, 2, 3, 5 and 6 and the range is 2, 3, 4, 6 and 7.
[The xcoordinates of the points are the domain and the y coordinates are the range.]
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