HP 39G Master Guide

255
T
T
h
h
e
e
‘
‘
S
S
y
y
m
m
b
b
o
o
l
l
i
i
c
c
’
’
g
g
r
r
o
o
u
u
p
p
o
o
f
f
f
f
u
u
n
n
c
c
t
t
i
i
o
o
n
n
s
s
The = ‘function’
Although this is listed in the MATH menu as if it were a function, it is not really.
Except in programming, the = sign is simply used in exactly the way that you
would expect it to be, mainly in the Solve aplet. It’s easier to obtain the = sign
directly from the keyboard.
ISOLATE(expression,var-name)
This function will rearrange a formula so that its subject is another variable.
To do this, the formula must be rewritten so that it is an expression which
equals zero. The ISOLATE function then rearranges the formula in terms of
that variable.
Eg. 1 Rewrite the formula
2
1
2
dat=
in ‘t’.
Firstly, rewrite as:
2
1
0
2
dat−=
Use: ISOLATE(D-AT
2
/2,T)
The result needs interpretation as the answer should be
2D
T
A
=±
. Firstly,
the ‘T=’ is missing and secondly, the symbol ‘S1’ stands for the
±
sign.
Eg. 2 Make X the subject of the formula
()
3
B
X
A
−
=
−
.
Using: ISOLATE(3/(X-A)+B,X)
gives: 3/-B+A
equivalent to:
3
X
A
B
−
=+.
The ISOLATE function is very useful within its
limitations, but it will not deal with a lot of
formulae. See right:
See also: The Solve aplet, FNROOT, QUAD

HP 39G Specifications

General

Brand	HP
Model	39G
Category	Calculator
Language	English