HP 15c User Manual
Page 231
Appendix D: A Detailed Look at _ 231
If
Error 8
is displayed as a result of a search that
is concentrated in a local ―flat‖ region of the
function, the estimates in the X- and Y-registers
will be relatively close together or extremely
small. Execute _ again using for initial
estimates the numbers from the X- and Y-
registers (or perhaps two numbers somewhat
further apart). If the magnitude of the function is
neither a minimum nor constant, the algorithm
will eventually expand its search and find a
more significant result.
Example: Investigate the behavior of the function
x
e
x
x
e
e
x
f
2
2
3
)
(
10
/
as evaluated in the following subroutine.
Keystrokes
Display
|¥
000–
Program mode.
´ b .0
001–42,21,.0
| a
002– 43 16
“
003– 16
x
e
.
'
004– 12
®
005– 34 Bring x-value into X-register.
| x
006– 43 11
x
e
x
2
.
*
007– 20
'
008– 12
2
009– 2
*
010– 20
x
e
x
e
2
2
.
“
011– 16
®
012– 34 Bring x-value into X-register.
| a
013– 43 16
“
014– 16
1
015– 1
0
016– 0