Lesson 18: solving for a variable— symbolically, 'th=q©/fl+tl, Si ©f s) ©q © © 4 © s) – HP 48G User Manual
Page 61
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Lesson 18: Solving for a Variable—
Symbolically
The HP 48 also allows you to isolate a varialhe syiiibolically—that is,
rearrange an expression so tliat the desired variable is isolated on one
side
of
the equal sign. Once
a
variable
is
isolated, it
is easy
to
save the
rearranged expression as its definition.
Exainpl*':
Solve for
T
h
in the following heat
transfer
equation, then
create variable
T H
containing the resulting equation:
U =
.4 ( T
h
- T
l
)
S t e p 1 :
Open the SYMBOLIC application and select I s o l a t
i U ® ®
^^^ISDLflTE ft
EKPR: IliillWiWilM^
VRIi:
RESULT: SymbO lie _ PRINCIPRL
ENTER EKPRESSIDH________________
jjatawiiiiiMiiiiiiMiiiiM
S t e p 2 :
Create and enter the equation.
SI
©f S) ©Q ©
© 4 © S)
@ © T l l Q T L
(ENTER)
^^*IS0LftTE ft MftRlftSLEl
erpr
:
'.'ftR:
RESULT: SymbO lie _ PRINCIPftL
ENTER EXPRESSION
■ftaiilMiliiiia—I
S t e p 3 :
Specify the variable of solution and solve for it
(© ©T (ENTER I
1:
'TH=Q©/fl+TL'
Solving Equations 5-7