Casio Prizm screenshot

[Don Shepherd]

Here is a screenshot from the Casio Prizm, showing the graph of two inequalities, y>=x+1 and y<2x+3. The dark shaded area is the solution to both inequalities. The actual screen looks somewhat crisper than the screenshot.

[Thomas Klemm]

What an improvement compared to what we can do with an HP-48G:

Since I'm not that familiar with plotting I had to consult the manual. You need two different plot-types: TRUTH and CONS.
As suggested in the manual I created two variables:

INEQ

'Y\>=X+1 AND Y<2*X+3'

EQNS

{ 'Y=X+1' 'Y=2*X+3' }

Now you can choose one or the other for EQ. Don't ERASE the graph after drawing the first plot.

---

Currently I'm reading the fun of programming.
There's a chapter dealing with images (7 Functional images). So I wondered whether I could do that with my HP-48 as well. Here we go:

Checker

checker

\<<

  FLOOR SWAP

  FLOOR + 

  2 MOD 

  NOT

\>>

EQ

\<< Y X checker \>>

Polar Checker

Make sure you have your calculator in RAD-mode.

toPolar

\<<

  R\->C DUP

  ABS SWAP ARG

\>>

n = 10

EQ

\<< 

  Y X

  toPolar

  \pi /

  n *

  checker

\>>

Swirl Vertical Strip

vstrip

\<< ABS .5 \<= \>>

fromPolar

\<<

  \-> r \Gh

  \<<

    \Gh SIN r *

    \Gh COS r *

  \>>

\>>

r = 1

EQ

\<<

  Y X toPolar 

  OVER 

  2 * \pi *

  r / +

  fromPolar

  vstrip

\>>

Now this turns out to be very slow. Moreover I received an "Insufficent Memory" error and had to plot the image in several runs. Not exactly what you want.

Still I hope these examples might be inspiring.

Best regards

Thomas