ZOOM 3:Zoom Out

In order to see the effects of a ZOOM option, a graph must already be displayed on the screen.  To learn how to enter and graph a function, go to Graphing a Function . For example, the function = is graphed below.  

Screen Picture of TI-83 Calculator

The ZOOM 3:Zoom Out option allows the user to select a new VIEWING RECTANGLE around a given point that is larger than the existing VIEWING RECTANGLE.  Both the Zoom In and Zoom Out results depend on the ZOOM FACTORS.

To select the ZOOM 3:Zoom Out option, first press the ZOOM key and then select 3. 

Screen Picture of TI-83 Calculator Screen Picture of TI-83 Calculator

Note: The X and Y coordinates may vary depending on what was last done on the calculator.  Whatever X and Y are displayed on the screen will remain in the center of the image.

Now press the ENTER key.  The VIEWING RECTANGLE will remain centered around the X and Y listed at the bottom of the screen, but the size of the VIEWING RECTANGLE will be 4 times of its orginal size (assuming Xfact and Yfact are both 4).  Thus, the standard VIEWING RECTANGLE of [-10, 10, 1] X [-10,10,1] is now [-40,40,1] X [-40,40,1].  See the result below.

Screen Picture of TI-83 Calculator

Note that because there are so many tick marks with Xscl and Yscl both set at 1, they blend into a line.  Pressing the ENTER key again will give a graph similar to the one shown below.  The new VIEWING RECTANGLE is [-160,160,1]  X [-160,160,1] .  The given function is hardly visible.  Zoom Out can reverse a Zoom In operation.

Screen Picture of TI-83 Calculator

The Zoom Out operations may also be centered on a point   See Zoom In to see how this is done.

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