Beginning a Trace
Moving the Trace Cursor
Moving the Trace Cursor from Function to Function
To move the trace cursor to any valid X value on the current function, enter the value. When you enter the first digit, an X= prompt and the number you entered are displayed in the bottom-left corner of the screen. You can enter an expression at the X= prompt. The value must be valid for the current viewing window. When you have completed the entry, press Í to move the cursor.
Note: This feature does not apply to stat plots.
If you trace a function beyond the left or right side of the screen, the viewing window automatically pans to the left or right. Xmin and Xmax are updated to correspond to the new viewing window.
While tracing, you can press Í to adjust the viewing window so that the cursor location becomes the center of the new viewing window, even if the cursor is above or below the display. This allows panning up and down. After Quick Zoom, the cursor remains in TRACE.
When you leave and return to TRACE, the trace cursor is displayed in the same location it was in when you left TRACE, unless Smart Graph has replotted the graph (page 3.15).
On a blank line in the program editor, press r. The instruction Trace is pasted to the cursor location. When the instruction is encountered during program execution, the graph is displayed with the trace cursor on the first selected function. As you trace, the cursor coordinate values are updated. When you finish tracing the functions, press Í to resume program execution.
Moving the Trace Cursor to Any Valid X Value Panning to the Left or Right Quick Zoom Leaving and Returning to TRACE Using TRACE in a Program
3-20 Function Graphing
8303FUNC.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:16 PM Printed: 02/19/01 1:35 PM Page 20 of 28
8303FUNC.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:16 PM Printed: 02/19/01 1:35 PM Page 20 of 28
To display the ZOOM menu, press q. You can adjust the viewing window of the graph quickly in several ways. All ZOOM instructions are accessible from programs. ZOOM MEMORY
1: ZBox Draws a box to define the viewing window. 2: Zoom In Magnifies the graph around the cursor. 3: Zoom Out Views more of a graph around the cursor. 4: ZDecimal Sets @X and @Y to 0.1.
5: ZSquare Sets equal-size pixels on the X and Y axes. 6: ZStandard Sets the standard window variables. 7: ZTrig Sets the built-in trig window variables. 8: ZInteger Sets integer values on the X and Y axes. 9: ZoomStat Sets the values for current stat lists.
0: ZoomFit Fits YMin and YMax between XMin and XMax.
When you select 1:ZBox, 2:Zoom In, or 3:Zoom Out, the cursor on the graph becomes the zoom cursor (+), a smaller version of the free-moving cursor (+).
To define a new viewing window using ZBox, follow these steps.
1. Select 1:ZBox from the ZOOM menu. The zoom cursor is displayed at the center of the screen.
2. Move the zoom cursor to any spot you want to define as a corner of the box, and then press Í. When you move the cursor away from the first defined corner, a small, square dot indicates the spot.
3. Press |, }, ~, or †. As you move the cursor, the sides of the box lengthen or shorten proportionately on the screen.
Note: To cancel ZBox before you press Í, press ‘. 4. When you have defined the box, press Í to replot
the graph.
To use ZBox to define another box within the new graph, repeat steps 2 through 4. To cancel ZBox, press ‘.
Exploring Graphs with the ZOOM Instructions
ZOOM Menu
Zoom Cursor
Zoom In magnifies the part of the graph that surrounds the cursor location. Zoom Out displays a greater portion of the graph, centered on the cursor location. The XFact and YFact settings determine the extent of the zoom. To zoom in on a graph, follow these steps.
1. Check XFact and YFact (page 3.24); change as needed. 2. Select 2:Zoom In from the ZOOM menu. The zoom
cursor is displayed.
3. Move the zoom cursor to the point that is to be the center of the new viewing window.
4. Press Í. The TI-83 adjusts the viewing window by XFact and YFact; updates the window variables; and replots the selected functions, centered on the cursor location.
5. Zoom in on the graph again in either of two ways. • To zoom in at the same point, press Í. • To zoom in at a new point, move the cursor to the
point that you want as the center of the new viewing window, and then press Í.
To zoom out on a graph, select 3:Zoom Out and repeat steps 3 through 5.
To cancel Zoom In or Zoom Out, press ‘.
ZDecimal replots the functions immediately. It updates the window variables to preset values, as shown below. These values set @X and @Y equal to 0.1 and set the X and Y value of each pixel to one decimal place.
Xmin=L4.7 Ymin=L3.1
Xmax=4.7 Ymax=3.1
Xscl=1 Yscl=1
ZSquare replots the functions immediately. It redefines the viewing window based on the current values of the window variables. It adjusts in only one direction so that @X=@Y, which makes the graph of a circle look like a circle. Xscl and Yscl remain unchanged. The midpoint of the current graph (not the intersection of the axes) becomes the midpoint of the new graph.
Zoom In, Zoom Out
ZDecimal
3-22 Function Graphing
8303FUNC.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:16 PM Printed: 02/19/01 1:35 PM Page 22 of 28
8303FUNC.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:16 PM Printed: 02/19/01 1:35 PM Page 22 of 28
ZStandard replots the functions immediately. It updates the window variables to the standard values shown below.
Xmin=L10 Ymin=L10 Xres=1
Xmax=10 Ymax=10
Xscl=1 Yscl=1
ZTrig replots the functions immediately. It updates the window variables to preset values that are appropriate for plotting trig functions. Those preset values in Radian mode are shown below.
Xmin=L(47à24)p Ymin=L4 Xmax=(47à24)p Ymax=4
Xscl=p/2 Yscl=1
ZInteger redefines the viewing window to the dimensions shown below. To use ZInteger, move the cursor to the point that you want to be the center of the new window, and then press Í; ZInteger replots the functions.
@X=1 Xscl=10
@Y=1 Yscl=10
ZoomStat redefines the viewing window so that all statistical data points are displayed. For regular and modified box plots, only Xmin and Xmax are adjusted.
ZoomFit replots the functions immediately. ZoomFit recalculates YMin and YMax to include the minimum and maximum Y values of the selected functions between the current XMin and XMax. XMin and XMax are not changed. ZStandard
ZTrig
ZInteger
ZoomStat
To display the ZOOM MEMORY menu, press q~. ZOOM MEMORY
1:ZPrevious Uses the previous viewing window. 2:ZoomSto Stores the user-defined window. 3:ZoomRcl Recalls the user-defined window. 4:SetFactors... Changes Zoom In and Zoom Out factors.
ZPrevious replots the graph using the window variables of the graph that was displayed before you executed the last ZOOM instruction.
ZoomSto immediately stores the current viewing window. The graph is displayed, and the values of the current window variables are stored in the user-defined ZOOM variables ZXmin, ZXmax, ZXscl, ZYmin, ZYmax, ZYscl, and ZXres.
These variables apply to all graphing modes. For example, changing the value of ZXmin in Func mode also changes it in Par mode.
ZoomRcl graphs the selected functions in a user-defined viewing window. The user-defined viewing window is determined by the values stored with the ZoomSto instruction. The window variables are updated with the user-defined values, and the graph is plotted.