HP 15c User Manual
Page 23
Section 1: Using
_ Effectively
23
If a root of g(x) is found, either the number e is not beyond the extreme value of f(x)
or else _ has found a different region where f(x) equals e. Revise e so that it is
close to—but beyond—the extreme value of f(x) and try _ again. It may also
be possible to modify g(x) in order to eliminate the distant root.
Example: Solve the previous example without calculating the derivative of the relative field
intensity E.
The subroutine to calculate E and the required constants have been entered in the previous
example.
In Program mode, key in a subroutine that subtracts an estimated extreme number from the
field intensity E. The extreme number should be stored in a register so that it can be manually
changed as needed
.
Keystrokes
Display
|¥
000-
Program mode.
´b1
001-42,21, 1
Begins with label.
GB
002- 32 12
Calculates E.
l9
003- 45 9
-
004- 30
Subtracts extreme estimate.
|n
005- 43 32
In Run mode, estimate the minimum intensity value by manually sampling the function.
Keystrokes
Display
|¥
Run mode.
10
´r
0.1745
v´B
-0.1029
30
´r
0.5236
Samples the function at
v´B
-0.2028
10°, 30°, 50°, …
50
´r
0.8727
v´B
0.0405