HP 48g Graphing Calculator - Manual (Page 268)

You can also make conditional transformations-
depends on a condition you specify.
-whether they occur
20
To replace a sybexpression with a different subexpression:
1. Press 17^ [SYMBOLIC 1 (Y) UK to display the M h HIPULflT
EoF form.
2. Press .‘ii.Y to open the N form.
3. Enter or insert the expression you wish to modify in the EXF'R:
field. (You maj nisfU’t an expression on level 1 of the stack bj'
pressing (NXTI ■ I i . C fNXT).)
4. Enter the symbolic pattern that you wish to replace in
the field. For generalized transformations, the
search pattern can contain “wildcard” names that match any
subexpressions. A
wildcard name consists of an & character
ENTER 1), and a valid variable name (&fl, KB, and Kn-arie
are examples).
5. Enter the new, replacement symbolic expression in the
F?EF i! field. In general, if )mu used wildcards in the
pattern expression, you should use wildcards in the replacement
expression. You may not use a wildcard in the replacement
expression that you did not use in the pattern expression.
6. Optional: Put a check-mark in the SUBEXF-'R FIRST field if
you want the search-and-replace to begin at the lowest level of
subexpressions and work “upwards” to the overall expression—a
good option if the substitution will simplify the expression. Leave
the field unchecked to begin the search with the overall expression
and work “dowmwards” to the low'er levels of subexpressions—a
good option if the substitution will expand the expression. Note
that a subexpression that already has been matched (and thus
replaced) is not a candidate for any further matches, nor are any
subexpressions wdiose arguments already have been matched.
7. Optional. Enter an expression representing a conditional test (such
as ‘ Z f---U ') The replacement will occur only if the test is true.
8. Press "ir to execute the search-and-replace in the chosen
“dirf'ction” and according to the conditional test, if any.
20-28 Calculus and Symbolic Manipulation