Texas Instruments TI-85 User Manual

Page 23

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Chapter 1

B-23

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To graph data on the TI-86:

The TI-86 has a built-in command to graph data and autoscale the data window.

Press

2nd

+

(

STAT

)

F3

(

PLOT

) to display the

STAT

PLOTS

screen. (Your screen may not look exactly like

this one.)

Note: When drawing a graph from the

y(x)=

list, you

may get an error message or see a scatter plot of ÒoldÓ
data as well as the function graph. If so, turn off the

STAT PLOTS

with

F5

(

PlOff

)

ENTER

.

On the

STAT PLOTS

screen, press

F1

(

PLOT1

) to dis-

play the

Plot1

screen, press

ENTER

to turn

Plot1 “On”,

press

F1

(

SCAT

)

. Press the menu key under

list

L

1

. Press

and the menu key under list

L

2

.

Press

and press the menu key corresponding to the

mark. You can choose any of the three marks at the
bottom of the screen.

You can enter the names of any

lists. However, it is easiest to
always work with

L1

and

L2

.

Press

EXIT

until you return to the home screen. Go to

the graph menu and clear the y(x)= list . To have the
TI-86 set an autoscaled view of the data and draw the

scatter plot, press

GRAPH

F3

(

ZOOM

)

MORE

F5

(

ZDATA

) .

(

ZDATA

does not reset the x and y-axis tick marks.

You should do this manually with

RANGE

or

WIND

if you want different spacing between the marks.)

You can trace the scatter
plot with the

TRACE

key.

Press

GRAPH

and access the function list. Notice that

Ò

Plot1”

at the top of the screen is now dark. This is

because you have turned

Plot1

ÒonÓ. If you always put

input data in list

L

1

and output data in list

L

2

, you can

turn the scatter plot off and on from the

y(x)=

screen

rather than the stat plots screen from this point on.
To turn

Plot1

off, use

to move the cursor to the

Plot1

position, and press

ENTER

. Reverse the process to turn

Plot1

back on.

A scatter plot is turned on when
its name on the

y(x)=

screen is

darkened. Remember that you

will have lower-case functions.

¥ TI-86 lists can be named and stored in the calculatorÕs memory for later recall and use. I f

you do this and use the list by its stored name, you must use the name of the list in the stat
plot setup or on the stat plot screen each time you change lists. Refer to your TI-86
Guidebook
for details.

1.4.6 FINDING FIRST DIFFERENCES

When the input values are evenly spaced, use

program

DIFF

to compute first differences in the output values. If the data are perfectly

linear (i.e., every data point falls on the graph of the line), the first differences in t h e

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