Inverts a point on the graph screen.

PtChg *x*, *y*

**Menu Location**

This command can't be found in any menu besides the command catalog.

This command works on all calculators.

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The `PtChg` command inverts a point on the graph screen — drawing it if it isn't already there, and erasing it otherwise. It uses point coordinates, which means that the result is determined by window variables: the x-coordinate must be between xmin and xmax, and the y-coordinate must be between ymin and ymax (with (xmin,ymin) being the bottom left and (xmax,ymax) the top right corner).

Unlike pixel commands such as `PxlChg`, however, `PtChg` won't give an error if the coordinates happen to be outside these bounds — it simply won't have any effect.

# Advanced Uses

`PtChg` can also be used with two lists of the same size. In that case, it will invert the points for every pair of elements (xlist[n], ylist[n]). This can be used as an alternative to plots (see `NewPlot`) to plot a set of points.