Using _ in a program, Restriction on the use of, For further information – HP 15c User Manual
Page 193
Section 13: Finding the Roots of an Equation 193
Restriction on the Use of _
The one restriction regarding the use of _ is that _ cannot be
used recursively. That is, you cannot use _ in a subroutine that is
called during the execution of _. If this situation occurs, execution
stops and
Error 7
is displayed. It is possible, however, to use _
with
f thereby using the advanced capabilities of both of these keys.
Memory Requirements
_ requires five registers to operate. (Appendix C explains how they
are automatically allocated from memory.) If five unoccupied registers are
not available, _
will not run and
Error 10
will be displayed.
A routine that combines _ and f requires 23 registers of space.
For Further Information
In appendix D, Advanced Use of _, additional techniques and
explanations for using _ are presented. These include:
How _ works.
Accuracy of the root.
Interpreting results.
Finding several roots.
Limiting estimation time.