Module 1  Describing Functions 
Introduction  Lesson 1  Lesson 2  Lesson 3  SelfTest 
Lesson 1.3: Describing Functions Numerically 
In Lesson 1.1 you defined the function f(x) = 2x^{2} – 5x – 3 and found its zeros with Guess and Check and by factoring. In Lesson 1.2 you graphed the function and found its zeros graphically. In this lesson you will represent the function numerically with a table and use the table to find the zeros. Creating a Table of Function Values To make a table of values for a function, you need to enter the function in the Y= Editor. You should have already done this in Lesson 1.1.
Displaying the Table Setup Screen Before you view the table, you should set its parameters.
Table Setup Parameters TblStart and Tbl The value in TblStart will be the first value of x in the table.
The value in Tbl determines how much x increases from one row to the next in the table. This value should be 1. Match the other settings in the figure shown below.
Finding Zeros from a Table The table provides numerical evidence for two zeros. One zero must exist between x = 1 and x = 0 because the corresponding values in Y_{1} change sign and the function is continuous, i.e., there are no breaks in its graph. The other zero is x = 3 because the corresponding value of Y_{1} is 0. You can get a better approximation of the zero between 1 and 0 by changing Tbl to 0.1.
This method of decreasing Tbl between two values in the table is called table zoom. 1.3.1 What zero is shown in the table above? Click here for the answer. Summarizing For r a real number, the following statements are equivalent:

< Back  Next> 
©Copyright
2007 All rights reserved. 
Trademarks

Privacy Policy

Link Policy
