HP 48G - Symbolic

SYMBOLIC
Enclosing an expression in algebraic syntax, ' ',
suppresses immediate evaluation of the result; you
must press [EVAL) explicitly. This lets you build and use
symbolic expressions with variables.
Example: [([1)+[eJX|ENTER) (youget ' 1+5");
(‘1-1"); Result: 'C1+HI*(1-H1!
To calculate with such expressions, use (=]SYMBOLIC).
It offers you a choice of six different calculation tools,
with a screen for each.
Solving a Quadratic Equation
Example: Solve symbolically for the (principal) solu-
tion of the quadratic equation 5x>~ 11x+2=0. Press
([©2JSYMBOLIC), use (¥) to highlight Zolwe quad..,
and press I[AM. In the EXPE: field (the arrow keys
willmove the highlightaround), use the EquationWriter
orthe command lineto enter 23¥#™2—11%5+2. In
the wnk: field, enter X (uppercase—it must match your
expression). In the KESULT: field, put Sumbio] 1o
(use the box and () as necessary). Select
PRIMCIPHL solution by putting a + (via FEi{oiTd). Now
you're ready to solve, so press Il ... '#=¢
Whenyou getyourresult, you also get the (<[SYMBOLIC]
menu, which offers other tools for altering, expanding
or using an algebraic expression (see the Command
Index, pages 41-77, for individual details):
(93)
COLCT| ERPAIS0L GUAD ZHOM [TAYLR
+MAT]+HMAT] *2 *@w] | |APPLY
oot ] ]
Now repeat the above quadratic sample but request
the general solution.... The 51 variable appears in
the solution as the + in the quadratic formula. To get
either of the two specific solutions, you store a—1 or
1 into the name =1, then request a numeric solution. *
The other five tools in (=]SYMBOLIC) have similar input
screens—note the self-explanatory prompts for each
field. More examples follow on the next 4 pages.--->
*You're actually altering the states of Flags -1 and -3 via the KEZULT: and
PRIMCIPAL: items on the quadratic input screen. Always bear in mind that
the states of Flags -1, -2 and -3 can affect the evaluation of a symbolic
expression—see page 78.
EQUATION] and (SYMBOLIC 21