HP 48g Graphing Calculator - Manual (Page 207)

18
Solving Equations
Solving an Equation for an Unknown Variable
To solve an equation for numeric answers bj' hand, you might use the
following general procedure:
1. Write down the equation you want to solve.
2. If possible, manipulate the equation to solve for the unknown
variable.
3. Substitute known values for the given variables.
4. Calculate the value of the unknown variable.
When you use the SOLVE application, you follow a similar
procedure—except you don’t need to do step 2 , and that simplifies the
process.
To sol¥6 an equation for an ynknown wariable:
1. Press solve ! ok .
2. Enter or choose the equation you wish to solve.
3. Enter values for all of the known variables.
4. Optional: Enter a guess value for the unknown variable. This can
make the search quicker or guide the root-finder to a particular one
of several possible roots for a given equation.
5. Move the highlight to the unknown variable and press iiSOLVEE.'
The SOLVE application can solve for the numeric value of a variable
in an equation, expression, or program:
■ Equation. An equation is an algebraic object containing = (for
example, ’ fl+B=C '). A solution is a value of the unknown variable
that causes both sides to have the same numeric value.
■ Expression. An expression is an algebraic object not containing =
(for example, ’ H + B + C ‘ ) . A solution is a root of the expression—a
18
Solving Equations 18-1