Flags - HP -28S Quick Reference

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Symbolic These are: e, i, MINR, MAXR, π. See Direct Key Commands.
constants
Flag 35 determines how these are evaluated:
• When set these symbolic constants evaluate to their symbolic form.
• When clear these symbolic constants evaluate to their numerical
Expressions, Flag 36 specifies how equations or functions with symbolic arguments are
Equations, evaluated:
Functions • When set, the evaluation of an expression is taken only a single step
• When clear, the variables are evaluated until a numerical result is
Consequences:
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General For testing and modifying flags see TEST Menu.
1 – 64 User flags without predefined meaning.
31 – 64 System flags:
31 LAST activated.
32 Protocol.
33 Printhead right.
34 Principal value.
35 Symbolic evaluation of constants.
36 Symbolic evaluation of functions.
37 – 42 Length of binary words (1-64), default is 64
43, 44 Binary number base. 00=decimal, 01=binary, 02=octal, 03=hex
45 Display in level 1: Single line or multi-line
46 (reserved)
To edit a program use the VISIT shortcut.
If a variable contains the name of a program only then the program is
executed when the variable is recalled.
If a program A contains the unquoted name of another program B,
the program B will be executed as a subroutine as soon as execution
of program A encounters the symbol B.
Use →NUM to convert them to numerical values.
value.
further by replacing variables with their contents (which may either be
another expression or a numerical value). EVAL may have to be
applied repeatedly to resolve all dependencies. Consider:
'A+B' 'A' STO A returns 'A+B'. After EVAL it is 'A+B+B' then
'A+B+B+B' etc.
reached. If a symbolic name is undefined an error occurs. Do not try
the above excample with flag 36 clear because it will produce an
endless recursion loop!!
In symbolic mode 'Q' 1/x returns 'INV(Q)' even if the variable Q
exists and has a numerical value. By pressing EVAL the expression is
evaluated and the numerical result returned.
In numeric mode an error occurs if Q is not an existing variable.
Otherwise Q is evaluated and a numerical result is returned.
Overall the symbolic evaluation mode seems to be more handy.
HP-28S

Flags

ALGEBRA Menu: ISOL and QUAD
BINARY menu: DEC, HEX, OCT, BIN
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MODE Menu: LAST
PRINT Menu: TRAC
See PRINT Menu.
See Evaluation Rules.
See Evaluation Rules.
BINARY menu: STWS
MODE menu: ML