Recognizing FunctionsDate: 09/30/2001 at 15:22:54 From: Miles Subject: Recognizing functions How do I know when there is a function on a graph? Date: 09/30/2001 at 19:41:52 From: Doctor Jodi Subject: Re: Recognizing functions Hi Miles, A function is something like this IN \ \ \ \____ | | | | | | ----\ \ \ \ OUT Where for each reasonable input, there's ONE output. Does this make sense? On a graph, we make the inputs x's and the output's y's. So the condition means that for each x there's ONE y. You can see if a graph is a function using the vertical line test. Does any vertical line through the graph intersect more than one place? If so, this ISN'T a function. But if EVERY vertical line through the graph intersects in one place (or none), then this IS a function. Does that make sense? Write back if you have more questions. - Doctor Jodi, The Math Forum http://mathforum.org/dr.math/ |
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