HP HP-28S - Page 93

If you know beforehand the region that you want to plot, you can
directly change the plotting parameters in PPAR. (PPAR is described
in detail in "PLOT" in the Reference Manual.) More often you need to
experiment to
find the desired plotting region. This manual shows
you how to use commands in the PLOT menu to Rhome in" on the
desired plot.
For
the second example, you'll plot the expression x
3
- x
2
- X + 3.
Put the expression in level 1.
~X.~3GX.~2GXGJ3
[ENTER I
Store the expression as the current equation.
sm Ir:=L:-:-~-mml--un:m--IDJiD--mIm--IDlJD---'1
Plot the expression.
DRAW
, , , , '/' I ' , , , , ,
The horizontal line is the axis for x, and the vertical line is the axis for
the value of the expression x
3
-
x
2
- X + 3.
This
plot shows a zero of the expression-a value of X for which the
value of the expression is zero. The zero is located where the graph of
the expression crosses the X axis. In the next chapter we'll use the
Solver to find a precise number for this zero.
To show more of the graph, expand the vertical scale and plot again.
Restore
the normal display of the stack.
~----------------------~
@ill 1
3
:
I
~mmlun:mlDJiDmImlDlJD
92 7: Plotting