# Ieval I Isolvei - HP -22S Owner's Manual

Scientific calculator.

Introduction to
I
EVAL
I
and
I
SOLVE
I
Functions
The following keys provide the ability to do calculations with
equations:
. , EQUATIONS I
Pressing .,
EQUATIONS I
displays the list of equations,
which stores equations that you enter. Press [!] or
.w
to roll through the list. The number of equa-
tions you can enter is limited only by the amount of
available memory. You can also enter algebraic ex-
pressions. (Expressions don't have two sides
separated by an "equals" sign). You can edit and clear
entries in the equation list.
.1
LIBRARY
I
Pressing . ,
LIBRARY
I
displays the equation library.
The library is a list of 16 permanent, built-in equa-
tions. Press [!] or
.w
to roll through the list. You
cannot edit or clear library equations. The library
equations are described in chapter 7.
, EVAL I
, EVAL I
calculates the value of the "unknown" variable
(the variable whose value you seek) when the equa-
tion has the form:
.'SOLVEI
.'EDITI
unknown variable
=
algebraic expression
The unknown must appear by itself on the left side
of the equation.
1
EVAL I
can also be used to evaluate
expressions.
1
SOLVE I
lets you solve the equation for any variable;
the unknown variable does not have to appear by it-
self, on the left side of the equation. Thus, ,
SOLVE I
saves you the trouble of having to rearrange the
equation yourself.
Allows you to change an equation after it has been
entered into the list of equations.
72
6: Evaluating and Solving Equations