Texas Instruments TI-89VSC Troubleshooting Guide - Page 4

TI-89 Guide TI 89-109 name before continuing. (See DELETING PROGRAMS OR OTHER INFORMATION FROM THE TI-89.) SYMBOLI C • I get a number instead of a symbolic expression. What is wrong? If you do not get a symbolic result, it is because the variable you are using as the input variable has a number stored in it. That is, the variable is a defined rather than an undefined variable. The variable you use for the input variable must be an undefined variable in order to obtain a symbolic result. Refer to the top of page TI89-5 of this Guide for more information. • Why is the symbolic result not correct when I am using several letters in the problem? One reason may be that the TI-89 thinks one of the variables is a function. For instance, if you have defined c as a function and in another problem want c to be a variable coefficient, you must indicate this when typing the expression: If you do not type c*(x + 5), the TI-89 assumes that you are evaluating the function c at the input value x +5 when you type c(x + 5). Copyright © Houghton Mifflin Company. All rights reserved.