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Plotting

The HP48G/GX is able to plot many different types of functions. To examine the possibilities, the `plot' screen needs to be opened. The key strokes 2pt tex2html_wrap609 tex2html_wrap1135 do this. The top line of this screen has two fields: TYPE and tex2html_wrap_inline1111 . Highlight the TYPE field by placing the cursor there. Push the menu button tex2html_wrap1137 . Five options are shown, and more can be seen by scrolling either down or up. At this time only the Function option will be discussed. Highlight this option by moving the cursor if needed. Then push the menu button tex2html_wrap1075 . If the field tex2html_wrap_inline1111 is not set to Rad (radians), highlight the field, and either toggle through the options by pushing the tex2html_wrap771 key, or use the tex2html_wrap1137 menu to place Rad in the field. Now place the cursor in the EQ field. To graph the function tex2html_wrap_inline1117 for values of x between -5 and 4, the HP48G/GX needs to have the function and the viewing area entered. Using algebraic notation, enter the expression tex2html_wrap_inline1121 into the EQ field. Tick marks are automatically inserted, you will not need to explicitly enter them. The field INDEP should show which variable is used in the EQ field. In this case it is X or x, depending on whether or not an upper case variable is used. Be sure it is the same as the variable used in your function. The H-VIEW field is used to control the values of X for which the function will be plotted. Move the cursor to the first H-VIEW field. Note: if you have not made a change in the field the cursor is on and push tex2html_wrap619 , the HP48G/GX returns to the home screen. To avoid this unwanted return use the cursor control buttons for any cursor movements. Once again, only use tex2html_wrap619 to change or insert an object into an highlighted field. If by some chance your HP48G/GX is no longer in the plot menu, return to it by pushing the keys 2pt tex2html_wrap609 tex2html_wrap1135 . Set the H-VIEW screen to -5 and 2. The cursor should now be in the AUTOSCALE field. If this field is checked, the HP48G/GX will automatically adjust the vertical viewing area, so that the graph of our function is visible. Check this field. The two rightmost menu options are ERASE and DRAW. Push tex2html_wrap1153 . This removes any previous plots. If this is not done, the HP48G/GX will keep what is currently in the plot, and draw our graph on top of it. This can be a useful feature when plotting different items from different menu screens, but not now. Push tex2html_wrap1155 . It seems to take forever for the plot to appear. This is because the HP48G/GX first computes function values in order to correctly set the V-VIEW field. The process is much faster if the AUTOSCALE feature is not used.

Your view screen should now show the graph of the function for x from -4 to 5. To view the plot without the menu overlay, push the subtraction key. This key functions as a toggle switch for the appearance or nonappearance of the menu. The tex2html_wrap1157 menu has various features that allow parts of the graph to be examined in more detail. Open it up and play with some of the menu items. By the way, don't forget that there may be more than just the six possibilities shown. Push the tex2html_wrap1103 key to see what is available. To return to the original menu displayed, push tex2html_wrap1103 until the tex2html_wrap1163 menu appears, and push it. The next two menu items tex2html_wrap1165 and tex2html_wrap1167 are very useful. The first is a toggle switch to turn on or off the coordinates of the cursor location. The second places the cursor on the curve that has been plotted. Push them both but tex2html_wrap1167 first. Notice the white box in the trace menu. This indicates that the trace feature is turned on. Now, using the cursor control keys, we can move the cursor along the curve and position it where we wish. This feature enables us to find approximate locations of extrema, zeros of the function, or other items of interest. Now open the FCN menu. There are a total of nine different sub-menus that can help explore various features of the graph of the function plotted. I again suggest playing with them.

Push the tex2html_wrap1163 menu, open up the tex2html_wrap1173 menu, and try out some of the menu items there.

After you are tired of playing in the plot menu push tex2html_wrap1077 to return to the plot screen, and then push tex2html_wrap1077 one more time to return to the standard screen. If you have been playing with some of the menu options in the FCN menu, there will be several computed values now stored on the stack. To see the graph of your function, without having to reopen the plot menu perform the following keystrokes. 2pt tex2html_wrap623 tex2html_wrap1181 .


next up previous
Next: Solving an Equation Up: How to Use the Previous: Memory

Mike Stecher
Thu Mar 21 09:53:31 CST 1996