Monday, July 3, 2017

Programming Languages: TI-85 vs. TI-84 CE Plus

Programming Languages:  TI-85 vs. TI-84 CE Plus

I purchased a 1995 edition of the TI-85 at a Pasadena City College swap meet.  The TI-85 was my go-to and favorite calculator through high school (1991 – 1995). 

Today, I am going to compare common programming commands between two of my favorite Texas Instrument calculators, the TI-85 and the current TI-84 CE Plus.  The manuals for each calculator were consulted to answer questions.

Arguments in vector brackets [ ] means the argument is optional.

TI-85 (1992 – 1997)
(probably also applies to the TI-86)
Software Version 10.0
TI-84 CE Plus (2016-)
(most of the this applies to TI-84 Plus 2004-present)
Software Version 5.2.2
Variable Names
Up to 8 characters, must begin with a number, no spaces.
All variables are global.
Single letters A through Z, n, θ
All variables are global.
Complex Number display, Rectangular
(X, Y)
X + Yi
Complex Number display, Polar
(R θ)
R e^θi
Graphing Modes
Function, Polar, Parametric, Differential Equation
Function, Polar, Parametric, Recurring Sequences
Number of Colors
0 (monochrome display)
15: blue, red, black, magenta, green, orange, brown, navy, light blue, yellow, white, light gray, medium gray, gray, dark gray (backlit display)
**CE and C versions only
Input by itself displays the graph screen

Input [“prompt string”], varname
Input by itself displays the graph screen

Input  [“prompt string”], variable
Prompt:  asking for and storing multiple values
Prompt var1, var2, var3 ,…
Prompt var1, var2, var3, …
Disp by itself displays the home screen

Disp var/string, [var/string …]
Disp by itself displays the home screen

Disp var/string, [var/string…]
Pause [var/string]
Pause [var/string], [time in seconds]
Wait time in seconds up to 100
Display the graph screen
displays the graph screen
displays the graph screen
Display the function table
Outpt(line, col, var/string)
8 lines, 21 columns
Output(row, col, var/string)
10 rows, 26 columns
InpSt stores entered text or equations as strings
N/A.  Use Input
If – Then – Else structure
If condition
do if true
do if false]
If condition
do if true
do if false]
For structure
For(var, begin, end, [step])
For(var, begin, end, [step])
While structure
While condition
do while condition is true
While condition
do while condition is true
Repeat – Until structure
Repeat condition
do while condition is false
Repeat condition
do while condition is false
Menu(nn, string, label…)
Where nn is from 1 to 15
Menu(“title”, “text”, label…)
Up to 9 options
Labels (Lbl/Goto)
Label names can have up to 8 characters.  All labels are local.
A-Z, 0 -99, θ.  All labels are local.
Increment (by 1) and Skip (if greater to value)
IS>(variable, value)
IS>(variable, value)
Decrement (by 1) and Skip (if less than value)
DS<(variable, value)
DS<(variable, value)
Stop program execution
Return from a subroutine
Execute a subroutine
Type the name of the program
Call program by pressing [prgm], choosing it from the Program submenu during editing
Clear the graph screen
ClDrw (clear all drawings)
ClrDraw (clear all drawings)
Display text on a graph screen
TextColor(color) sets the color.
Text([-1], row, col, string)
0-164 row pixel,
0-264 column pixel
-1 is for large text
Draw a temporary function
DrawF f(x)
DrawF f(x), [color]

Draw a temporary inverse function (f^-1(x) = y, x and y are swapped)
DrInv f(x)
DrawInv f(x), [color]
Shade (lower, upper, left, right)
Shade (lower, upper, [left, right, pattern, pattern resolution, color])
Draw a line
Line(x1, y1, x2, y2)
Line(x1, y1, x2, y2, [0/1, color, line style])
0/1: 0 to erase, 1 to draw
Draw a circle
Circle(x, y, radius)
Circle(x, y, radius, [color, line style])
Draw a Point
Only the TI-84 Plus CE has similar commands for pixels
Pt-On(x,y, [mark, color])
Convert a value to a string
eval(expression) → Str#
No complex results
Convert a string to a value
Convert a string to a graph variable
St>Eq(string, graph variable)
String>Equ(string, graph variable)
Length of a string
lngth string
(call from the catalog)
Extract part of a string
sub(string, begin point, length)
sub(string, begin point, length)
(call from the catalog)
Execute Linear Regression analysis (other regressions are similar)
LinR xlist, ylist
LinReg(ax+b) xlist, ylist, [freqlist, Y= variable]
Turn a stat plot on
N/A (stat plots are not available on the TI-85)
PlotsOn [1,2,3]
Turn a stat plot off
N/A (stat plots are not available on the TI-85)
PlotsOff [1,2,3]
Turn graph functions on
FnOn [1 – 99]
FnOn [1-9, 0]
Turn graph functions off
FnOff [1 – 99]
FnOff [1-9, 0]


As we can see, the programming language of the TI-85/86 family is similar to the TI-84 Plus family, translating the programs should not be difficult.  I believe that stat plots are available on the TI-86, but not the TI-85.

Keep in mind if you have complex numbers, that the complex mode on the TI-84 Plus (a+bi or re^(θi) has to be turned on.  Furthermore, logarithmic, power, exponential, and trigonometric functions for complex numbers return error on the TI-84 Plus (substitute expressions must be used).

(use radians mode)
With z = X + Yi = R*e^(θ*i), X = real(z), Y = imag(z), R = abs(z), θ = arg(z)

z^n = R^n * (cos(n*θ) + sin(n*θ)*i), n is a real number
ln (z) = ln R + θ*i
e^(z) = e^X * cos Y + e^X * sin Y * i
sin(z) = sin X * cosh Y + cos X * sinh Y * i
cos(z) = cos X * cosh Y – sin X * sinh Y * i
sin¯¹ (z) = asin(z) = -i * ln (zi ± √ (1 – z^2)
z1 ^ z2 = e^(z2 * ln z1)


This blog is property of Edward Shore, 2017

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