HP 39g Graphing Calculator - Manual (Page 157)

Symbolic functions
= (equals)
ISOLATE
LINEAR?
QUAD
The symbolic functions are used for symbolic manipulations
of expressions. The variables can be formal or numeric, but
the result is usually in symbolic form (not a number). You will
find the symbols for the symbolic functions = and I {where) in
the CHARS menu (|
shift |c/-MRS) as well as the MATH menu.
Sets an equality for an equation. This is not a logical operator
and does not store values. (See “Test functions” on page 10-
20
.)
expression I = expression!
Isolates the first occurrence of variable in expression=Q and
returns a new expression, where variable=newexpression.
The result is a general solution that represents multiple
solutions by including the (formal) variables si to represent
any sign and nl to represent any integer.
ISOLATE {expression, variable)
Examples
ISOLATE ( 2 * X + 8 , X ) returns -4
ISOLATE ( A + B * X / C , X ) returns - ( A * C / B )
Tests whether expression is linear for the specified variable.
Returns 0 (false) or I (true).
LINEAR? (expression, variable)
Example
LINEAR? ( {X''2-D / ( X + l ) , X ) returns 0
Solves quadratic expression=0 for variable and returns a new
expression, where variable=newexpression. The result is a
general solution that represents both positive and negative
solutions by including the formal variable SI to represent any
sign: + or - .
QUAD (expression, variable)
Example
QUAD { ( X - I ) ^ - 7 , X ) returns
( 2 + s I * 5 . 2 9 1 5 0 2 6 2 2 1 3 ) / 2
Using mathematical functions 10-19