All About Functions
Date: 11/06/96 at 08:19:27 From: bonie Subject: All About Functions Hi Doc, I would like a complete explanation of functions. Thanks a lot, Doc!
Date: 03/21/97 at 15:07:02 From: Doctor Matthew Subject: Re: All About Functions Functions are one of the most important ideas in mathematics. One of the most simple ways to think about functions is as a machine: you put something into the machine, and it spits something back out. For example, when I used to go to the zoo, they had these cool machines that would make plastic gorillas while you watched. You'd put three quarters into the machine and two minutes later a hot plastic gorilla would fall out of the machine. This is like a function: the input to the function was three quarters, and the output of the function was a plastic gorilla. So in general, a function is a set of rules for taking input and producing output. Most of the time when you talk about functions in math the input and output are numbers. If I've got a function called Fred, and I input the number 5, Fred might output 10. If I input the number 3, Fred might output 6. It just so happens that Fred is the "take a number and double it" function. You could write this as Fred(x) = 2x, which says that whatever the value of x is, the value of "Fred of x" will be twice it. You could also imagine functions that take more than one number as their input, like f(x,y) = x+y. That means that if you give the function numbers 8 and 5 as input, the function spits out the number 13 as output. There's a lot more about functions out there, certainly lots more than we can tell you right now, but there's a lot more information in our archives. Good luck! -Doctors Matthew and Ken, The Math Forum Check out our web site! http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.