ZoomFit, ZoomStat, ZSquare, and ZInteger Commands on TI83 Plus
The ZoomFit and ZoomStat Zoom commands on the TI83 Plus graphing calculator help you find an appropriate viewing window for the graph of your functions. The ZSquare and ZInteger Zoom commands readjust the viewing window of an alreadygraphed function.

ZoomFit: This is a popular Zoom command. If you know how you want to set the xaxis, ZoomFit automatically figures out the appropriate settings for the yaxis.
To use ZoomFit, press [WINDOW] and enter the values you want for Xmin, Xmax, and Xscl. Then press [ZOOM][0] to get ZoomFit to figure out the ysettings and graph your function. ZoomFit does not figure out an appropriate setting for Yscl, so you may want to go back to the Window editor and adjust this value.

ZoomStat: If you’re graphing functions, this command is useless. But if you’re graphing Stat Plots, this command finds the appropriate viewing window for your plots.

ZSquare: Because the calculator screen isn’t perfectly square, graphed circles won’t look like real circles unless the viewing window is properly set. ZSquare readjusts the existing Window settings for you and then regraphs the function in a viewing window in which circles look like circles.
To use ZSquare, graph the function, and then press [ZOOM][5]. The graph automatically appears.

ZInteger: This command is quite useful when you want the trace cursor to trace your functions using integer values of the xcoordinate, such as when graphing a function that defines a sequence. ZInteger readjusts the existing Window settings and regraphs the function in a viewing window in which the trace cursor displays integer values for the xcoordinate.
To use ZInteger, graph the function, and then press [ZOOM][8]. Use the
keys to move the cursor to the spot on the screen that will become the center of the new screen. Then press [ENTER]. The graph is redrawn centered at the cursor location.