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Unformatted text preview: 02 + y 2 = 4 Þ y2 = 4 Þ y = ±2 So, this equation is not a function. Recall, that from the previous section this is the equation of a
circle. Circles are never functions.
[Return to Problems] Hopefully these examples have given you a better feel for what a function actually is.
We now need to move onto something called function notation. Function notation will be used
heavily throughout most of the remaining chapters in this course and so it is important to
understand it.
Let’s start off with the following quadratic equation. y = x2  5x + 3
We can use a process similar to what we used in the previous set of examples to convince
ourselves that this is a function. Since this is a function we will denote it as follows, f ( x ) = x2  5x + 3
So, we replaced the y with the notation f ( x ) . This is read as “f of x”. Note that there is nothing
special about the f we used here. We could just have easily used any of the following, g ( x ) = x2  5x + 3 © 2007 Paul Dawkins h ( x ) = x2  5x + 3
177 R ( x ) = x2...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.
 Spring '12
 MrVinh

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