Chapter 2 Section 3

Introduction to Functions Goal:Find domain and range, determine if it’s a function, use function notation and evaluate. Definition of a function A function is a relationship between two variables such that each value of the first variable is paired with exactly one value of the second variable. The domain of a function is the set of all possible values of the first variable. The range of a function is the set of all possible values of the second variable.

Determine if you have a function {(2,3),(4,8),(-1,2),(2,3),(0,9)} 2. {(1,3),(5,0),(4,3),(2,8),(-1,3),(1,4)} 3. {(1,5),(2,5),(3,5),(4,5),(5,5)} How to determine if you have a function! Step 1Determine if any of the x-values repeat. NO then you have a function YESgo to step 2 Step 2Determine if the x has the same y-values. NO then you DO NOT have a function Yesthen you do have a function

Is the graph a function? 1.2. Vertical Line Test If every vertical line intersects a given graph at no more than one point, then you have a function.

Function Notation f(x) = 2x 2 – 3x + 7 Examples: 1.Find f(3) 2.Find f(-2) 3.Find f(0)

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