HP 48gx User Manual

Lesson 18: Solving for a Variable—
Symbolically
The HP 48 also allows you to isolate a variable symbolically—that is,
rearrange an expression so that 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.
Example: Solve for Ty in the following heat transfer equation, then
create variable TH containing the resulting equation:
q
Uv=-——1
A (Ty — Tp)
Step 1: open the SYMBOLIC application and select I=zil
2a
@ vio
OOO
2% ISOLATE A YARIAELE 23
EXPE:
VAR:
RESULT: Symbol ic _ PRINCIPAL
ENTER EXPRESSION
EDIT CHOOS] | JEANWGL| Ok
Step 2: Create and enter the equation.
(EQUATION) ISOLATE A VARIABLE 33
UEC)
RE)
3
U=0
CAs
CTH-TL
YAR:
AX @&E) RESULT: Symbolic PRINCIPAL
(@)(@) TH (=) TL
ENTER EMPRESSION
ECT [CHOOSE] | [CAMEL] OK |
Step 3: Specify the variable of solution and solve for it.
WV @T @H Ls TH=OAL RTL
VECTR| MATE] LIST HYP REAL EASE]
Solving Equations 5-7

HP 48gx Specifications

General

Model	HP 48gx
Type	Graphing Calculator
Display Type	LCD
Display Size	131x64 pixels
Memory	128 KB RAM
Expandable Memory	Yes, via expansion cards
Release Year	1993
Processor	Saturn
Programming Language	RPL
Power Supply	3x AAA batteries
Weight	255 g (9 ounces)