Using Solve In A Program - HP -32S Owner's Manual

Using SOLVE in a Program
You can use the SOLVE operation as part of a program. If appropri
ate, include or prompt for initial guesses (into the unknown variable
and into the X-register) before executing the SOLVE variable instruc
tion. The two instructions for solving an equation for an unknown
variable appear in the program as:
FN= label
SOLVE variable
Labeling Output. The programmed SOLVE instruction does not pro
duce a labeled display (variable-value) since this might not be the
significant output for your program (that is, you might want to do
further calculations with this number before displaying it). If you do
want this result displayed, add a VIEW variable instruction after the
SOLVE instruction.
Conditional Execution if No Solution. If no solution is found for
the unknown variable, then the next program line is skipped (in ac
cordance with the 'Do if True* rule, explained in chapter 6). The
program should then handle the case of not finding a root, such as by
choosing new initial estimates or changing an input value.
Example: Time Value off Money. The 'Time Value of Money" pro
gram in chapter 14 solves loan and savings problems by solving for
an unknown in the given TVMequation. This equation is defined as a
function in routine T, which relates the variables for present balance,
future balance, payment, interest rate, and number of payments.
124 7: Solving ffor an Unknown Variable in an Equation