Introduction to Functions & Function Notation
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Relation : a set of ordered pairs
Domain: the set of input values (x-values);
the independent variables.
Range: the set of output values (y-values);
the dependent variables.
Function: a relation in which each value in
the domain is assigned to exactly one value
in the range.
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Year, x
Rate per 1000
People, y
2000
14.7
2001
14.1
2002
13.9
2003
14.1
2004
14.0
2005
14.0
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Use the Vertical Line Test: If a vertical
line can be drawn that will intersect
the graph at more than ONE point,
then it is NOT a function!
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Consider the equation y = 2x + 1. That is a
function.
To re-write using function notation, just
replace y with f(x).
So, y = 2x + 1 becomes…
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f(x) = 2x + 1
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Given the graph of a function, f(x) represents
the y-value for a specific x. Find where the
graph is at that x and state the y-value.