Algebra Day 1

Slide 1

• To be a function or not to be a function
• 9/12/2017
• •What do you remember about functions?
• •What determines a function?
• Definitions
• •Relation: relationship between sets; the x-values and y-values of all ordered pairs. If you have two sets of values, and the number x is in Set 1 and y is in Set 2, (x,y) is considered the relation of the sets
• •Relation: “any set of ordered pairs”
• Definitions
• •Function: a type of relation; a relation where there is a set of inputs and a set of outputs where there is exactly one output to each input.
• •Function: “a relation where each input has exactly one output”
• •Functions can be represented in a variety of ways
• •Graph, table, ordered pairs, mapping, equation, or words
• Function: each input has exactly one output
• Function
• Not a Function
• -
• Function: each input has exactly one output
• Function
• Not a Function
• (4,12)
• (5,15)
• (6,18)
• (7,21)
• (8,24)
• (4,12)
• (4,15)
• (5,18)
• (5,21)
• (6,24)
• Evaluate a Function
• •Function notation: a way of representing functions algebraically
• Example: f(x)=3(x-2) “f of x”
• •If you were give an input (x) and a function written in function notation f(x), can you determine the corresponding output? How??
• Yes, by substituting the given value for x
• Example: find f(1), f(4)
• f(1)=3(1-2)=3(-1)=-3
• f(4)=3(4-2)=3(2)=6
• •Or given f(x)=9, find x
• f(x)=9
• 3(x-2)=9
• x-2=3
• x=5

Mapping

Vertical line test