5.5+Revisiting+Jean’s+Problem+0910

[|Book1.xls] MMS May 5/2010 Math 7B

Big Idea =Negative numbers help us to model many real world situations.=

Table for Jean's tune ups versus profit (Problem 5.2):

A 1. In the table of data you made in problem 5.2, what range of values did you use for the number of tune-ups? 2. What range of values did you use for the profit? B Enter the profit equation into your calculator. Use the number of tune-ups as the //x// variable and the profit as the y variable. Use your answers to part A to help you decide to adjust the window setting so that you will be able to see the graph of the profit equation. Press GRAPH to display the graph. Make a sketch of the graph you see on the screen.  C How is the break-even point shown on the graph? D Look at the table of data on your calculator. How is the break-even point shown in the table? **  The break-even point isn’t shown in the table; it just shows before and after the breakpoint. This is because after her 13th tune-up, she is still short $20, but after her 14th tune-up, she has $40. This shows that the breakpoint is somewhere between her 13th and 14th tune-up.
 * Negative #'s in parentheses in table. Example (800) = -800.**
 * Tune Ups || 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11 || 12 || 13 || 14 || 15 || 16 || 17 || 18 || 19 || 20 ||
 * < Profit ($) ||< (800) ||< (740) ||< (680) ||< (620) ||< (560) ||< (500) ||< (440) ||< (380) ||< (320) ||< (260) ||< (200) ||< (140) ||< (80) ||< (20) ||< 40 ||< 100 ||< 160 ||< 220 ||< 280 ||< 340 ||< 400 ||
 * The range I chose for the tune-ups was 0 -20. **
 * The range I used for the profit was (-800) – 400. **