HP HP-28S - Page 257

Program
<~ E~-(PAt~ :"
t'WL T I
,,:: COLCT »
t'WL TI
I ENTER I
c::] EXCO I STO I
Comments
Begin the program.
Put EXPAN on the stack.
Execute EXPAN until the alge-
braic object doesn't change.
Put COLCT on the stack.
Execute COLCT until the alge-
braic object doesn't change.
End the program.
Put the program on the stack.
Store the program as EXCO.
Example. Expand and collect completely the expression
3x (4y + z) + (8x - 5z)2.
Enter the expression.
I USER I
c::]30X0
[D 4 0 Y G z .rn G
[D 8 0 X G 5 0 Z .rn .~ 2
I ENTER I
Expand and collect completely.
EXCO
Expressions with many products of sums or with powers can take
many iterations of EXPAN to expand completely, resulting in a long
execution time for EXCO.
256 28: Programming Examples