HP 48gII - Manual (Page 400)

Page 12-19
• • The @ZOOM key, when pressed, produces a menu with the options: In, Out,
Decimal, Integer, and Trig. Try the following exercises:
• • With the option In highlighted, press @@@OK@@@. The table is expanded so
that the x-increment is now 0.25 rather than 0.5. Simply, what the
calculator does is to multiply the original increment, 0.5, by the zoom
factor, 0.5, to produce the new increment of 0.25. Thus, the zoom in
option is useful when you want more resolution for the values of x in
your table.
• To increase the resolution by an additional factor of 0.5 press @ZOOM,
select In once more, and press @@@OK@@@. The x-increment is now 0.0125.
• To recover the previous x-increment, press @ZOOM —@@@OK@@@ to select
the option Un-zoom. The x-increment is increased to 0.25.
• To recover the original x-increment of 0.5 you can do an un-zoom
again, or use the option zoom out by pressing @ZOOM @@@OK@@@.
• The option Decimal in @ZOOM produces x-increments of 0.10.
• The option Integer in @ZOOM produces x-increments of 1.
• • The option Trig in produces increments related to fractions of π, thus
being useful when plotting trigonometric functions.
• To return to normal calculator display press `.
Plots in polar coordinates
First of all, you may want to delete the variables used in previous examples
(e.g., X, EQ, Y1, PPAR) using function PURGE (
I @PURGE). By doing this, all
parameters related to graphics will be cleared. Press J to check that the
variables were indeed purged.
We will try to plot the function f(
θ) = 2(1-sin(θ)), as follows:
• First, make sure that your calculator’s angle measure is set to radians.
• Press „ô, simultaneously if in RPN mode, to access to the PLOT
SETUP window.
• Change
TYPE
to
Polar
, by pressing @CHOOS ˜ @@@OK@@@.
• Press ˜ and type:
³2* „ Ü1-S~‚t @@@OK@@@.