Texas Instruments TI86 User Manual - Page 101

Chapter 6: Graph Tools 89 In the example, the function y(x)=x^3+.3x2-4x is graphed. The numeric display mode settings do not affect coordinate display. Using the Free-Moving Cursor When you select GRAPH from the GRAPH menu, the graph screen is displayed with the free-moving cursor at the center of the screen. The cursor appears as a plus sign with a flashing center pixel. To move the cursor, press ", #, !, or $; it moves in the direction of the cursor key you press. ♦ In RectGC format, each cursor movement updates the variables x and y. In PolarGC format, each cursor movement updates x, y, R, and q. ♦ In CoordOn format, the x and y cursor coordinates are displayed at the bottom of the graph screen as you move the cursor. Graphing Accuracy The coordinate values displayed as you move the cursor approximate actual mathematical coordinates, accurate to within the width and height of the pixel. As the difference between xMin and xMax and between yMin and yMax becomes smaller (for example, when you zoom in on a graph), graphing is more accurate and coordinate values approximate the actual mathematical coordinates more closely. The free-moving cursor coordinates represent the cursor location on the graph screen. Moving the free-moving cursor precisely from one plotted point to the next along a function is very difficult. To move along a function easily, use the trace cursor (page 90).