Finding Your Position on a Football Field

Date: 11/1/95 at 15:31:22
From: Navigator
Subject: help on a function

Suppose you start at the goal line of a football field and walk 
toward the other goal line.  After you have walked x yards, you 
will be on the  F(x) yard-line. For example, after you walk 60 
yards you are on the 40 yard line.  Write a function F(x) that 
represents your position on the football field after walking x 
yards from the goal line. Give the domain of this function and the 
range of your function.

Could you please assist me on this problem.  Your help is greatly 
appreciated.

John Reichel  102344.1331@compuserve.com

Date: 11/3/95 at 14:57:30
From: Doctor Ken
Subject: Re: help on a function

Hello!

Here's a hint that may help you solve this problem.  Try using the
"absolute value" function.  It's defined by Abs(x) = Sqrt{x^2}.  
Its graph looks like this:

                             ^
                             |
                             |     
                  \          |          /
                   \         |         / 
                    \        |        /
                     \       |       /
                      \      |      /
                       \     |     /
                        \    |    /
                         \   |   /
                          \  |  /
                           \ | /
                            \|/
-----------------------------|--------------------------->
                             |                     x-axis
                             |
                             |
                             |
                             |
                             |
                             |
                             |
                             |y-axis


Where the v actually goes off at 45 degree angles to the x- and y-
axes.

Good luck!

-Doctor Ken,  The Geometry Forum