Class notes 10-26

To illustrate the difference between a function and a non-function, we used the example of a rule for boys asking girls to go out.

A boy can only ask ("------>" symbol in a mapping diagram) one girl to go out.  That's a function.
It's OK for one girl to be asked out by more than one boy.

If a boy asks ("------>" symbol in a mapping diagram) more than one girl to go out, that's not a function.
It's not OK for two different girls to be asked out by the same boy.


 Homework for Friday 10-28 - because of the trip to see the play - is page 72, item 15, all four parts.


You can remember the proper sequence of pairs of terms by looking at the alphabeticl order of the first letters.

Domain first, Range second.  D comes before R in the alphabet
x first, y second.  X comes before Y in the alphabet
Input first, Output second.   I comes before O in the alphabet