Introducing Functions

True or false: The relation is a function.

• False

• True

What is f(1)?

• 2

• 3

• 1

• 4

Which variable is the independent variable?

• x

• y

• z

True or false: The graph shows a relation.

• False

• True

Is the relation above a function?

• Yes because all inputs x have unique outputs y.

• No because some inputs x have duplicate outputs y.

Is the relation a function? Why?

• Yes, because the x-value 11 has two y-values paired with it.

• Yes, because each x-value has only one y-value paired with it.

• No, because the x-value 11 has two y-values paired with it.

• No, because each x-value has only one y-value paired with it.

Is this mapping a function or not a function? 

• Function

• Not a Function 

How would you write y = 2x - 3 in function notation?

• y = 2x-3

• f = 2x - 3

• f(x) = 2x - 3

• Can't be written in function notation

What is the definition of a function?

• Has inputs and outputs

• Every input has only ONE output

• Inputs have different outputs every time

• x-values and y-values

Is this table a function or not a function? 

• Function

• Not a Function