III. Working With A Graph

A. y(x) Menu -Equation Editor

Pressing opens the equation editor, the y(x) menu.

You use this screen to enter a function (or functions) that you want to graph. The window that is opened is essentially the same in all graph modes. The Key Strokes shown below are after you have opened the equation editor. You can turn a function on or off, change the style of the graph, etc.

Menu
Function
Key Strokes
x
Enters the variable x where the cursor is located.
y
Enters the variable y where the cursor is located.
INSF
Inserts a deleted equation name above the cursor.
DELF
Deletes the selected function.
SELCT
Turns a function on and off for graphing.
ALL+
Turns all of the functions "on".

ALL-
Turns all of the functions "off".

STYLE
Seven graphing styles are available.

x: You can use this to enter the variable x, or you can use .

y: Use this when you need to enter a y into an equation, usually when you want to refer to another equation.

Perform algebraic operations on an
equation to create other equations.
Graph derivatives of equations.

INSF: When you delete an equation (see the next topic), you can reinsert the equation number using INSF. However, the equation will not be shown, only the equation number. This is demonstrated below with DELF.

DELF: If you have several equations entered and wish to delete some or all of them, move the cursor to the equation number and press DELF.

Several functions.
To delete function y2
move the cursor to y2.
Press DELF.
Insert the number y2
by moving the cursor
to y3 and pressing INSF.

SELCT: This key will turn an equation "on" or "off". If the equation is "on", the equal sign is dark and it will graph. If the cursor is "off", the equal sign is clear and the function will not graph. To use SELCT, move the cursor to the equation line.

Equation y2 is on.
Press SELCT and
y2 is now off.

ALL+: This will turn all of the equations on at once.

ALL-: This will turn all of the equations off at once.

STYLE: This key makes seven different graphing styles available. This can be very useful if you are graphing more than one function. Open the equation editor and press . You will see the STYLE option at . As you press the graph style will change. Each style is shown below.

1. Line: This is the default setting and graphs will be a thin solid line. Use ZDECM.

Enter the function.
Graph is solid thin line.

2. Thick: The graph will appear as a thick line. If you have two graphs, this option applied to one of the graphs will allow you to distinguish between them easily. Move the cursor to y1 and press . The LINE mode changes to THICK.

Put y1 in thick mode.
Graph of y1 will be thick.
Graph of y2 is a line.

3. Shade above: This will shade the area above the graph. To change the shading style, go to the DRAW menu.

This is the symbol
for Shade Above.
Graph will be shaded above.

4. Shade below: This will shade the area below the graph. To change the shading style, go to the DRAW menu.

This is the symbol
for Shade Below.
Graph will be shaded below.

5. Path: This will trace the path of the graph as it is plotted with a circular cursor moving through the graph as it is drawn. This can be useful when graphing in parametric mode, or when graphing more than one function on the same screen.

This will trace the
path as it is graphed.
The path will
be traced out.

6. Animate: This will trace the path of the graph but will not show the graph.

Access the
animate mode.
Graph path will
be traced only.

7. Dot: When in this mode, the points are not connected. This mode is useful when you are graphing functions that have vertical asymptotes or piecewise defined functions.

Access dot mode.
Points will not
be connected.
A. y(x)
B. MATH
C. FORMAT
D. EVAL
E. TABLE
F. TRACE
G. ZOOM