Appendix D: A Detailed Look at
_
227
Special consideration is required for a different
type of situation in which
_
finds a root
with a nonzero function value. If your
function's graph has a discontinuity that
crosses the
x-
axis
,
_
specifies as a root
an
x-
value adjacent to the discontinuity. This is
reasonable because a large change in the
function value between two adjacent values of
x
might be the result of a very rapid,
continuous transition. Because this cannot be
resolved by the algorithm, the root is displayed
for you to interpret.
A function may have a
pole,
where its
magnitude approaches infinity. If the function
value changes sign at a pole, the corresponding
value of
x
looks like a possible root of your
equation, just as it would for any other
discontinuity crossing the
x-
axis. However, for
such functions, the function value placed into
the Z-register when that root is found will be
relatively large. If the pole occurs at a value of
x
that is
exactly
represented with 10 digits, the
subroutine may try that value and halt prematurely with an error indication.
In this case, the
_
operation will not be completed. Of course, this
may be avoided by the prudent use of a conditional statement in your
subroutine.
Example:
In her analysis of the stresses in a
structural component, design consultant Lucy
I. Beame has determined that the shear stress
can be expressed as
14
10
for
1000
10
0
for
350
45
3
Q
2
3
x
x
x
x
where
Q
is the shear stress in newtons per
square meter and
x
is the distance from one end in meters. Write a
subroutine to compute the shear stress for any value of
x.
Use
_
to
find the location of zero shear stress.
Summary of Contents for HP-15C
Page 1: ...HP 15C Owner s Handbook HP Part Number 00015 90001 Edition 2 4 Sep 2011 ...
Page 17: ...Part l HP 15C Fundamentals ...
Page 64: ......
Page 65: ...Part ll HP 15C Programming ...
Page 118: ...118 ...
