Directions for the Graphing Calculator

 

Plotting graphs of equations

 

A.  Entering equations

 

      a.   Press 2nd  STATPLOT (on top, above y=).  Make sure that all plots are turned       off.

      b.   Press y= (on top), and clear any existing equations.  Enter equations to be       graphed.  For an equation to be graphed, the equal sign must be highlighted.  To       highlight the = sign, move the curser to it and press ENTER.

      c.   Select Graph to see your graphs.

 

B.  Tables

 

      a.   Once you have entered an equation, you can see a table of values by selecting      2nd TABLE (above GRAPH).

      b.   You can change the values in the table by selecting 2nd TBLSET (above       WINDOW).  In particular, if you don’t see two columns of data in the TABLE,       you should check TBLSET to make sure that AUTO is selected in the case of       both in independent (INDPNT) and dependent (DEPEND) variables.      

     

C.  The viewing window:  options for creating a good window for viewing your graphs.

 

      a.   Select ZOOM and then choose ZSTANDARD, then ENTER.  This sets a 20 x    20 window (x is between -10 and 10 and y is between -10 and 10) for the graph

      b.   Choosing your own window:

               1.      Select WINDOW.

               2.      Enter values for XMIN, XMAX, YMIN, YMAX.  (Leave XSCL and                          YSCL as is.) 

               3.      To get estimated values for #2, use the TABLE to see values for the                           equation that you have selected.

              

D.  Finding points on the graph

 

      a.   When an equation has been graphed, select the TRACE key (on the top row).        The cursor will appear on the graph, and the x- and y-coordinates of that point       will be displayed.

 

E.   CALC:  The CALC key menu, 2nd CALC (above the Trace key) has seven applications that can be used with a graph. The two most useful for us are VALUE and INTERSECT.

 

      a.   VALUE:  This key can be used to evaluate the function at any value within the       range [Xmin, Xmax]. You can repeat the process by entering other values. If you       enter a value that is outside the range, you will get an error message.

            i.          Enter an equation on the y= screen. 

            ii.         Select CALC, then VALUE, then press ENTER.  The screen will show the

                        graph of the equation and a flashing x=  prompt.

            iii.       Enter a value for x between Xmin and Xmax.

 

      b.   INTERSECT:  This key can be used to find the point(s) in intersection of two       graphs.

            i.          Enter two equations on the y= screen.

            ii.         Using TABLE, find a window that shows the two graphs intersecting.

            ii.         Select CALC, then INTERSECT, then ENTER.  Select ENTER three                           more times.    

     

     

A good site for learning more:

http://www.prenhall.com/divisions/esm/app/graphing/ti83/