Class Home Class Table Next Class

Graphing Calculator's Zooming Feature

  • No points have been marked on this page for BREAKs. Decide for yourself when to break.
  • Keep notes open.
    On this pages find notes on:
  • The Purpose of Zoom
  • How to Zoom

Why Zoom?  
      WINDOW and ZOOM are two feaautres that facilitate viewing a graph and reading approximate values of data from the graph using TRACE.
      WINDOW features set individual window parameters -- like the left-most x value (Xmin) or the right-most x value (Xmax) -- and are used when one knows some information about how a graph looks and wishes to adjust the details of the viewing screen.
      ZOOM features adjust more than one window parameter quiclky, simultaneously. [Perhaps the speed at which this happens reminds one of the speed of a racing vehicle as it zooms by.]
    Some ZOOM options are listed below.
  • BOX - (explained below) enlarges a rectangular box on the existing graphing window.
  • IN - resizes the screen in (showing more detail) on a preset scale using the curser value as a center.
  • OUT - resizes the screen out (showing more of the entire graph but with less detail) on a preset scale using the curser value as a center.
  • STANDARD - returns the viewing window to the default window centered at the origin and displayed so the axes (the x-axis and y-axis)are square, or have the same scale.
  • PREVOIUS - returns to the previously used viewing window.
  • SQUARE - adjust the window, centered around the curser, so the axes are the same scale.
      Below, ZOOM BOX is described.

How to ZOOM BOX  
1st: Store the function in the y= menu.
2nd: Press the GRAPH key to display the graph of the function.
3rd: Press TRACE and move to the right or left on this function to display a decimal approximation of the x value and the y value, the value of the function.
4th: If the decimal approximation of the y value changes in the first two decimal digits, it is necessary to redraw the function with a different viewing window.
5th: Press ZOOM then 1 for BOX to return to the graph to select the corner of a new window.
6th: Move the curser to a point which will serve as one corner of a new viewing window.
I like keeping the viewing window the same shape as the viewing window of the calculator. I pick a corner which builds this shape rectangle about the region of the graph which needs enlargeing.
7th: Press ENTER to make the corner "stick" and watch how the curser changes shape on the screen.
8th: Move the curser to the diagonally opposite corner and watch as the new rectangular screen is created by your use of the curser.
9th: Press ENTER to make the corner "stick" on the new corner and watch as the graph is redrawn with better resolution.
10th: Repeat steps 3 through 9 until curser movement does not produce a change in the first two decimal digits of the y value.
d.) To keep a function in storage but not display the graph,
1st: Go to the y= menu
2nd: Move to the equal sign on the line with the desired function.
3rd: Press ENTER (on a TI82 or TI83) so that the equal sign is no longer highlighted.
3rd: Press Deselect (on a TI85 or TI86) on the soft key pad.

Class Home Class Table Next Class

    This page is brought to you by MATHEMATICAL CONCEPTS, inc., publishers of MATH SPOKEN HERE!, ISBN: 0-9623593-5-1.

    You are hereby granted permission to make ONE printed copy of this page and its picture(s) for your PERSONAL and not-for-profit use. YOU MAY NOT MAKE ANY ADDITIONAL COPIES OF THIS PAGE, ITS PICTURE(S), ITS SOUND CLIP(S), OR ITS ANIMATED GIFS WITHOUT PERMISSION FROM: or by mail to the address below.


85 First Street, Keyport, NJ 07735-1503   (732) 739-3951

© 2002, A2,

[MC,i. Home] [Order form] [MSH! Home] [Transcription] [Table] [Words] Classes [top] [end]