Texas Instruments TI-85 - Manual (Page 5)

B-5 Copyright © Houghton Mifflin Company. All rights reserved.
Chapter 1 Ingredients of Change:
Functions and Linear Models
&
1.1 Fundamentals of Modeling
There are many uses for a function that is entered in the graphing list. Graphing the function
in an appropriate viewing window is one of these. Because you must enter all functions on one
line (that is, you cannot write fractions and exponents the same way you do on paper) it is
very important to have a good understanding of the calculatorÕs order of operations and to
use parentheses whenever they are needed.
1.1.1 ENTERING AN EQUATION IN THE GRAPHING LIST Press
GRAPH F1 ( y(x)= ) to access the graphing list. Up to 99 equations can be entered in t h e
graphing list, and the output variables are called by the names y 1 , y 2 , etc. When you intend
to graph an equation you enter in the list, you must use x as the input variable.
If there are any previously entered equations that you will
no longer use, clear them out of the graphing list. Position the cursor on the line
containing the equation and
press CLEAR or F4 ( DELf ) .
Suppose you want to graph A = 1000(1 + 0.05) t . Because we intend to graph this equation,
the input must be called x. Type x by pressing x- VAR or F1 ( x ) , not the times sign ✕ .
TI 85 For convenience, we use the first, or y 1 , location
in the graphing list. Enter the right hand side as
1000(1 + 0.05)^ x
TI 86 For convenience, we use the first, or y 1 , location
in the graphing list. Enter the right hand side as
1000(1 + 0.05)^ x
Plot1 , Plot2 , and Plot3 at the top of the y(x)= list should
not be darkened. If any of them are, use until you
are on the darkened plot name. Press ENTER to make
the name(s) not dark.
1.1.2 DRAWING A GRAPH If you have not already done so, enter the equation in t h e
y(x)= list using x as the input variable before drawing a graph. We now draw the graph of
y = 1000(1 + 0.05) x .