HP HP-28S - Redefining the Corners of the Plot

Return to the stack display.
IONI
The coordinates of the digitized point, represented by a complex
number, are in level 1.
Redefine the center of the plot, using CEHTR on the next menu row.
INEXTI CEHTR If: I
.IIIlmIIDBlmBtmmlImIIKI:II.
The coordinates are taken from the stack and used to adjust the plot
parameters. Unlike
*H ,CEHTR doesn't change the scale.
Try
another plot.
.1 PREy I DRAW
I"" ,i1:"", ,I
Now zoom in on an interesting part of the plot. You could use *H
again, using a fractional scaling factor. (For example, a scaling factor of
.5 would return the vertical scale to its original value.) But there's a
more flexible way to zoom in on a plot.
Redefining the Corners of the Plot
This time you'll digitize two points, one for the lower-left corner of
the new plot and one for the upper-right corner, to zoom in on the
plot.
Move
the cross hairs to the desired lower-left corner.
I"" ,~i<"" ,I
94 7: Plotting