HP HP-15C - Page 231

Appendix D: A Detailed Look at _ 231
If Error 8 is displayed as a result of a search that
        
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
ex
x
eexf



2
23)(
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
ex

2
.
*
007– 20
'
008– 12
2
009– 2
*
010– 20
x
ex
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