There is no such thing as an INPUT FUNCTION. The phrase refers to using the identity function as a picture of the input of a function and the graph of the function itself as the output function so as to make comparison of the input to the output easy, providing a vehicle for describing the action of a function.

This is a page from the dictionary MATH SPOKEN HERE!, published in 1995 by MATHEMATICAL CONCEPTS, inc., ISBN: 0-9623593-5-1.   You are hereby granted permission to make ONE printed copy of this page and its picture(s) for your PERSONAL and not-for-profit use.

© 2005, Agnes Azzolino www.mathnstuff.com/math/spoken/here/1words/i/i16.htm