Realations and Functions >>>>>HELP PLEASE>

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Countrygal

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Dec 10, 2005
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Question: Use the vertical-line test to determine whether each realtion is a function
{(5,0), (0,5, (5,1), (1,5)}


i'm not really sure how to do these kind of problems and i need some help...thanks
 
ya, but i was gone like a week and i have nooo clue what to do.. i guess i'm a slow learner ... who knows... thanks
 
The vertical line test is actually very simple. In order to be considered a function, and equation must meet a few requirements. One of these requirements is that "For every x, there must be only one y." So, if you sketch the graph of a line, any vertical line drawn on the graph should not touch more than one point. So, if you draw a line straight down, and it hits two or three points, the sketched line is NOT a function. :) It's that simple ;)!
 
If you are given points like in the question that you posted, you don't need a sketch, just notice that the first and third points have the same x value but different y values, hence that the graph, whatever it looks like, cannot be a function because it won't pass the vertical line test.
 
This is very true. Good point. I wasn't thinking to write that. Yes, if you have a list of points and some have the same x value, then it is not a function.
 
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