TI-85 QUICK REFERENCE GUIDE

By Gary A. Harris

Department of Mathematics

Texas Tech University

Lubbock, Texas 79409

g.harris@ttu.edu

GRAPH package (rectangular coordinates)

y(x)=	Place to enter and edit functions to be graphed

x	Independent variable

y	Dependent variable (needs integer to indicate
which previously defined function to use)

INSf	Inserts a function into the list if space permits

DELf	Deletes designated function from list

SELCT	On/Off switch to determine which functions
in list are to be graphed

ALL+	Turns all functions on

ALL-	Turns all function off

RANGE	Used to manually set viewing window

xMin=	Sets minimum x

xMax=	Sets maximum x

xScl=	Sets spacing between hash marks on x axis

yMin=	Sets minimum y

yMax=	Sets maximum y

yScl=	Sets spacing between hash marks on y axis

Observations:

1. There are 127 pixels horizontally across the screen. So the step size for sampling x is

h = (xMax - xMin) / 126 .

2. Arithmetic operations can be used in defining the viewing window. For example, if you wish to sample evey 5 integers starting with 0, simply set

xMin = 0 and xMax = 5(126).

Note that xScl=1 is not very good for this window, xScl=50 might be better. On the other hand, if you want the sample step size to be .01 with 0 at the center set

xMin=-126/200 and xMax=126/200.

3. The fact that 126 is even tells us that the center of the interval [xMin , xMax] is always a sample point because

xMin + 63 h = (xMax + xMin) / 2.

ZOOM	Used to automatically change viewing window

BOX	Creates a view box which becomes viewing
window (Position cursor and ENTER to create one	corner, then position cursor and ENTER to create	opposite corner)

ZIN	Zooms in centered on cursor position

ZOUT	Zooms out centered on cursor position

ZSTD	Sets default viewing window (xMin = yMin = -10,
xMax = yMax = 10, xScl = yScl = 1)

ZPREV	Returns to previous viewing window

ZFIT	Choses "best window" to fit the graph

ZTRIG	Choses "best window" for viewing trig graphs

ZDECM	Choses xMin = - 6.3 & xMax = 6.3 so 0 is the
center and h = .1)

ZRCL	Recalls a stored window

ZFACT	Used to set the "Zoom factors" (default is 4 for
x and y, i.e. ZIN divides the x and y distances by 4)

ZOOMX	Multiplies x-distance by x-factor

ZOOMY	Multiplies y-distance by y-factor

ZINT	Sets xMin = -63 & xMax = 63 (so h = 1)

ZSTO	Stores the current window

TRACE	Begins with cursor at the center of the graph of y1

Rt arrow traces to right in increments of h

Lt arrow traces to left in increments of h

Dn arrow jumps to the graph of y2 with same x-coord .

Etc. (x and y coordinates of cursor appear on screen)

GRAPH	Graphs all functions that are turned on (in current
window)

MATH	Contains most of the mathematical concepts of Cal I

LOWER	Sets a lower bound on x

UPPER	Sets an upper bound on x

ROOT	Searches for a root within the bounds on x

dy/dx	Computes the derivative at the cursor position on
the graph (TRACE is automatically activated)

f(x)	Computes the integral between lower limit (1st
ENTER) and upper limit (2nd ENTER) (TRACE is	automatically activated)

FMIN	Computes the min of f within the bounds on x

FMAX	Computes the max of f within the bounds on x

INFLC	Seeks an inflection point of f within the bounds on x

YICPT	Seeks the y intercept

ISECT	Seeks an intersection point between two graphs
within the bounds on x (TRACE is automatically
activated and used to estimate the point and	determine the two graphs)

DIST	Computes the straight line distance between two
points on a graph (TRACE is automatically
activated)

ARC	Computes the arc length between two points on a
graph (TRACE is automatically activated)

TANLN	Draws the tangent line to a point on a graph and
displays its slope (TRACE is automatically
activated)

DRAW	Used for drawing pictures but appears to have little computing
ability

Shade	Graphs and shades the area between two graphs

(Shade(y1,y2,a,b) graphs y1, y2, and shades in the	region above y1, below y2, from x = a to x = b)

LINE	Draws the line segment between two points (1st
cursor position ENTER, and second cursor position	ENTER)

VERT	Draws vertical line through cursor position (with as
many positions as you wish < 126)

CIRCL	Draws a circle with center the lst cursor position
ENTER and radius determined by the second
DrawF	Draws the graph of F (DrawF y1)

PEN	Allows the cursor to be used as a pen

PTOFF	Turns the designated pixel off

PTON	Turns the designated pixel on

PTCHG	Turns on pixel off and off pixel on

CLDRW	Clears all the drawn stuff from the screen (returns
the graphed stuff)

TanLn	Draws the tangent line to the specified function at
the specified value of x (TanLn(y1, x) draws the	tangent line to y1 at (x,y1(x))

DrInv	Draws the inverted graph of the specified function

(DrInv y1 draws the inverted graph of y1)

FORMT	Lets you change various graphing format options

RectGC PolarGC	Displays coordinates in rectangular of polar form

CoordOn CoordOff	Displays coordinates or does not display coords

DrawLine DrawDot	Connects points with lines or does not

SeqG SimulG	Graphs functions in order or simultaneously

GridOff GridOn	Does not display coord grid or does display it

Osazone AxesOff	Displays coord axes or does not display them

LabelOff LabelOn	Does not label x & y or does label x & y

STGDB	Stores current graphs up to 5 (data and all)

RCGDB	Recalls any of the stored graphs (data and all)

EVAL	Evaluates y for given x (can jump between graphs)

STPIC	Stores current picture up to 5

RCPIC	Recalls any of the stored pictures