The coordinate cursor allows you to use the mouse to select any point on the graphing screen and display its coordinates. This feature is available both in the button bar and in the Tools menu. To turn on the coordinate cursor, select the Coordinate Cursor option in the Tools menu, click the Coord cursor button, or press Ctrl+U ⌘U. The mouse pointer will change into crosshairs to make it easier to spot particular points and the coordinate that it is currently at will be displayed in the status bar. As you move the pointer around, the status bar will continue to display its current position. Note that this display is in polar coordinates when you have polar graph paper selected.
If you want finer control of the exact cursor position, you can use the arrow keys to move one pixel at a time (holding down on a key moves progressively faster).
When you move the cursor close enough to one of the curves on-screen, it will automatically "lock on" to make it easier to trace the path of the curve. When this happens, the equation of the curve being traced is also displayed in the status bar. The crosshair will stick to the curve you chose, even if it intersects other graphs, as long as you move the cursor gently in the general direction of the curve. If you use the arrow keys appropriate to the slope of the curve (up/down for a steep slope or left/right for a more horizontal slope) and don't hold down the keys too long, the cursor will also stick to the curve. To release the cursor from a curve, move perpendicularly to the slope of the curve at that point, or just move quickly in any direction.
Note that you cannot access the menu or move the pointer out of the graphing screen while the coordinate cursor is active. Turn the coordinate cursor off by clicking either mouse button or pressing Ctrl+U.
As a shortcut, you can also turn the coordinate cursor on by holding down the RIGHT mouse button while positioning the crosshairs over the point you want to inspect. The coordinate cursor is on, exactly as described above, until you release the mouse button.