Path: utzoo!attcan!uunet!convex!killer!ames!pasteur!ucbvax!hplabs!hp-pcd!hpspkla!nungeste
From: nungeste@hpspkla.HP.COM (Dick L. Nungester)
Newsgroups: comp.sys.hp
Subject: HP-28S Quick Reference Guide
Message-ID: <3520001@hpspkla.HP.COM>
Date: 26 Aug 88 18:35:30 GMT
Organization: Hewlett Packard Company, Spokane, Wa.
Lines: 110

As I read the Owner's Manual and Reference Manual for the 28S, I took the
following notes.  Hope you find them useful:

HP-28S Quick Reference Guide, 08/26/88 by Dick Nungester

Menus (27 total, listed by access, then functionality)
  - Shift on left keypad:   17 (ARRAY...TEST, CATALOG and UNITS)
  - Shift on right keypad:   4 (MODE, LOGS, PLOT, CUSTOM)
  - Key on right keypad:     4 (<cursor>, TRIG, SOLV, USER)
  - Nested in other menus:   2 (FORM in ALGEBRA, SOLVR in SOLV)

  - Menus of commands:      20 (ALGEBRA...TRIG; Owner's Manual p.193 & App. D)
  - Menus of operations:     4 (<cursor>, CATALOG, UNITS, FORM)
  - Menus of variables:      2 (SOLVR, USER)
  - User-defined menu:       1 (CUSTOM)

Calculus
  - SYMBOLIC differentiation (of practically anything)
    - All-at-once: 'TAN(X^2+1)' 'X' d/dx >>> <derivative>
    - Step-by-step: 'dX(TAN(X^2+1))' EVAL EVAL ...
  - SYMBOLIC integration (of Taylor approximations to any function)
    - 'COS(X)' 'X' 2 <integrate> >>> '<2+1 degree polynomial answer>'
  - NUMERIC integration (of practically anything)
      - explicit: (0.001 is desired % accuracy; 0.002 is +/- absolute error)
        - 'SIN(X)' { X 0 <pi> } 0.001 <integrate> >>> 2.000 0.002
      - implicit:
        - << SIN >> { 0 <pi> } 0.001 <integrate> >>> 2.000 0.002 
  - TAYLR (Taylor approximations to any function)
    - 'COS(X)' 'X' 4 TAYLR >>> '< 4th degree Taylor polynomial>'

Plotting
  - INS digitizes a point.
  - DEL puts a string conversion of the display on the stack (like LCD->).
  - <cursor menu> held down displays the current cursor coordinates.
  - PPAR = { Pmin Pmax independent_variable resolution Paxes }
  - Plotting an equation instead of an expression plots both sides.

SOLV menu (In QUAD and ISOL, s<n> = +/- 1; n<n> = 0, +/- 1, +/- 2, ...)
  - QUAD (Take the 2nd order Taylor approximation, then solve the quadratic.)
    - 'COS(X)' 'X' QUAD >>> '-(s1*1.414)'
    - 'A*X^2+B*X+C' 'X' QUAD >>> '(-B+s1*<root>(B^2-4*A*C))/(2*A)'
      - (Use FORM's COLCT on two "extra" divides to get the above form.)
  - ISOL (isolate the first occurance of '<var>')
    - 'A*(X+3)-B=C' 'X' ISOL >>> '(C+B)/A-3'
  - SOLVR
    - Always tends toward x axis: + local mins or - local maxs can be found.
    - To use: STEQ; SOLVR; values to knowns, guess to unknown; shift, unknown.
      - Guess to unknown: number (duplicated and perturbed to 2) or {lo_end
        hi_end} (region search will begin in) or {best_guess lo_end hi_end}.
        Any can be complex (digitized points) and only real part is used.
      - During solving, ATTN interrupts to see progress, leaving a 3-number
        list on the stack to resume by "<unknown> (list to var), <shift>, 
        <unknown> (continue solving)".  Any other key shows algorithm settle.
      - Zero (exact), Sign Reversal (bracketed), Extremum (zero f'(x)).
  - ROOT is just the command form of SOLVR ("1" below is a guess at 'X')
    - 'SIN(X)=COS(X)' 'X' 1 ROOT >>> 0.785 (RAD mode)

Unit conversions
  - 1 "kg*m/s^2" "dyn" CONVERT >>> 100000 "dyn"
    - only 1 "/" in compound units

Programs (lower case are clauses)
  - Decision
    - IF test THEN true END (IFT); IF test THEN true ELSE else END (IFTE)
  - Error Trap
    - IFERR trap THEN error END; IFERR trap THEN error ELSE normal END
  - Definite Loop
    - start finish START loop NEXT; start finish START loop step STEP;
      start finish FOR name loop NEXT; start finish FOR name loop step STEP
  - Indefinite Loop
    - DO loop UNTIL test END; WHILE test REPEAT loop END

Reserved variable names
  - EQ (SOLVR and plots); PPAR (plots); <sigma>PAR, <sigma>DAT (stats);
    s<n> (ISOL and QUAD); n<n> (ISOL); der... (user-defined derivatives)

Four classifications of operations (ambiguous terms in the manuals)
  - Operations
      - Non-programmable (INS, PREV, ENTER, ON, ...) or "Operation"
      - Commands
        - RPN (SWAP, DROP, LAST, RCL, PURGE, ...) or "Command"
        - Functions
          - Non-Analytic (ABS, IP, MAX, %CH, ...) or "Function"
          - Analytic (SIN, EXP, INV, LN, +, =, ...) or "Analytic Function"

Entry Modes
  - Immediate (numbers, lists, arrays; open box cursor) 
  - Algebraic (names and algebraics; striped box cursor)
  - Alpha (strings and programs; solid box cursor)

System Operations
  - Print display:           ON L
  - Contrast Control:        ON + or ON -
  - Attention:               ON
  - System Halt:             ON <up>
  - Memory Reset:            ON INS <right>
  - Repeating Test:          ON <left>
  - Keyboard Test:           ON NEXT
  - Cancel System Operation: ON DEL

Miscellany
  - PUT: <array or list> index element PUT >>> <new array or list>
  - GET: <array or list> index GET >>> element
  - PUTI: <array or list> index element PUTI >>> <new array or list> <index+1>
  - GETI: <array or list> index GETI >>> <array or list> <index+1> element
  - FORM menu (in ALGEBRA): ENTER returns to main FORM menu.
  - Flags 1-30 general use, 31-64 calculator modes.
  - Binary integers are unsigned -- base (b, o, d, h) effects display only.
  - Symbolic constants MINR, MAXR, e, pi, i.
  - Type-ahead buffer of 15 keys.