Sharp EL-9900 - Manual (Page 142)

9
Advanced Keyboard/PROGRAMMING USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
1. Program the calculator to graph the Sierpinski triangle, which is an infinite
set of nested equilateral triangles. The graph is generated from a
construction of a fractal by means of an iterated system, or in other words,
playing a chaos game.
2. Create a new program with the name SIERPINS. Enter the following program
and remember to press ENTER at the end of each line. If you make a mis
take, use the calculator’s editing features to correct the error.
3. Enter the following program:
random
⇒X
MATH C 1 STO X/
θ/T/n ENTER
random
⇒Y
MATH C 1 STO ALPHA Y ENTER
1
⇒I
1 STO ALPHA I ENTER
Label A PRGM B 0 1 ALPHA A ENTER
random
⇒N
MATH C 1 STO ALPHA N ENTER
If N>(1
÷3) Goto B
PRGM B 0 3 ALPHA N MATH
F 3 ( 1
÷
3 ) PRGM B 0
2 ALPHA B ENTER
.5(X+1)
⇒X
. 5 ( X/
θ/T/n + 1 ) STO X/θ/T/n
ENTER
.5Y
⇒Y
. 5 ALPHA Y STO ALPHA Y
ENTER
Goto D PRGM B 0 2 ALPHA D ENTER
Label B PRGM B 0 1 ALPHA B ENTER
If N
≤(2÷3) Goto C
PRGM B 0 3 ALPHA N MATH
F 6 ( 2
÷ 3 )
PRGM B 0
2 ALPHA C ENTER
.5(X+.5)
⇒X
. 5 ( X/
θ/T/n + . 5 )
STO
X/
θ/T/n ENTER
.5(Y+1)
⇒Y
. 5 ( ALPHA Y + 1 ) STO
ALPHA Y ENTER
Goto D PRGM B 0 2 ALPHA D ENTER
Label C PRGM B 0 1 ALPHA C ENTER
THE SIERPINSKI TRIANGLE