Texas Instruments TI-83 PLUS - Manual (Page 145)

TI-83 Plus Function Graphing 142
ZSquare
ZSquare replots the functions immediately. It redefines the viewing
window based on the current values of the window variables. It adjusts in
only one direction so that
@ X= @ Y , which makes the graph of a circle look
like a circle. Xscl and Yscl remain unchanged. The midpoint of the
current graph (not the intersection of the axes) becomes the midpoint of
the new graph.
ZStandard
ZStandard replots the functions immediately. It updates the window
variables to the standard values shown below.
Xmin= L 10 Ymin= L 10 Xres=1
Xmax=10 Ymax=10
Xscl=1 Yscl=1
ZTrig
ZTrig replots the functions immediately. It updates the window variables
to preset values that are appropriate for plotting trig functions. Those
preset values in
Radian mode are shown below.
Xmin= L (47 à 24) p Ymin= L 4
Xmax=(47 à 24) p Ymax=4
Xscl= p /2 Yscl=1