HP 48g Graphing Calculator - Manual (Page 255)

Isolating a Single Variable
To solve for a variable
that appears
only once:
1. Press ri^fSYMBOLICl ff1 ffl ffl OK t o open t h e ISOLATE H
form.
2. Enter the expression or equation to be solved into the EXPRs field.
If the algebraic is an expression (it has no =), the expression is
treated as an equation of the form ' expression'-^ ' .
3. Enter the variable you wish to solve for into the VflR! field. The
variable to be isolated can be the argument of a function only if the
HP f
8
has an inverse for that function. Functions for which the
HP 48 has inverses are called analytic functions in this manual. For
example, you can isolate .Y in an algebraic containing or
LHO-O because TAN and LN have inverses (ATAN and EXP).
However, you cannot isolate A in an algebraic containing IPO-1).
The operations index in appendix H identifies the HP 48 analytic
functions.
4. Optional: Select the result type you wish. (Numeric will attempt
to compute a numerical solution and generate an error message if it
fails.)
5. Optional: Check the ... field if you only want to see the
6.
principal solution (see “Getting General and Principal Solutions’’
on page 20-16).
Press UK to solve for the variable.
20
Solving Quadratic Equations
to open the :3uLvE
To solve
for
a variable in a
quadratic:
1. Press frRfSYMBOLICl (A) |T)
QUADRA TIC form.
2. Enter the quadratic equation or expression you wish to solve in the
ED-IPR: field. If the algebraic is an expression, the expression is
treated as an equation of the form ' expression=0 ’. Tf you supply
an equation that is not first or second order in the variable to be
solved for, it will be transformed into a second order polynomial
approximation before being solved as a quadratic.
3. Enter the variable you wish to solve for in the VARs field. If the
algebraic contains other variables, they must not exist in the
current directory if you w-ant those variables to be included in the
Calculus and Symbolic Manipulation 20-15