HP 39g+, User Manual

Page: 161 / 294

Using mathematical functions 11-17
Symbolic functions
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 | (
where ) in the CHARS menu
(
CHARS
) as well as the MATH menu.
= (
equals
)
Sets an equality for an equation. This is not a logical
operator and does not store values. (See “Test functions”
on page 11-18.)
expression1 = expression2
ISOLATE
Isolates the first occurrence of variable in expression= 0
and returns a new expression, where
variable=newexpression. The result is a general solution
that represents multiple solutions by including the (formal)
variables
S1 to represent any sign and n1 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)
LINEAR?
Tests whether expression is linear for the specified
variable . Returns
0
(false) or
1
(true).
LINEAR?(
expression , variable
)
Example
LINEAR?((X^2-1)/(X+1),X)
returns
0
QUAD
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
S1 to represent any sign: + or – .
QUAD(
expression , variable
)
Example
QUAD((X
-
1)
2
-7,X)
returns
(2+s1*5.29150262213)/2