Cursor action 
 
   

This better graphing window will be the background for many of our displays in the future. Just for reference, we do mark the maximum and minimum values of x and y on the axes. Click on the Action button to get the improved graph. Play around with the cursor until you are familiar with the display.

You may have noticed that the more convenient marker that was used to indicate the y value was a line connecting the previous and the current values. Since there were only 11 points across the screen where y was actually calculated, the graph is obviously made up of straight-line segments. If we increased the number of calculated points the appearance of the graph smoothes out and any point on the curve lies quite close to an actual value for the function.

On the Cursor Action display try moving the cursor to place it precisely on one of the plotted points. You will discover one of the limitations of computer graphics. The resolution of the screen is limited. The actual value of our function may fall between two adjacent "pixel" locations so the cursor cannot hit it exactly. Pixels by the way are the little lighted spots on the screen that make up any picture.

In addition to the cursor, we have provided a way to permanently mark any point of interest on the graph. Press the mouse button to place a little cross hair at the cursor location. This allows you to mark a point and still use the cursor to do other things. The marker x and y values will be displayed in the lower margin to the right.

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