HP HP-15C

Appendix D: A Detailed Look at _ 229
Keystrokes
Display
| ¥
Run mode.
7 v
7.0000
Initial estimates.
14
14
´_ 2
10.0000
Possible root.
))
1,000.0000
Stress not zero.
The large stress value at the root points out that the _ routine has
found a discontinuity. This is a place on the beam where the stress quickly
changes from negative to positive. Start at the other end of the beam
(estimates of 0 and 7) and use _ again.
Keystrokes
Display
0 v
0.0000
Initial estimates.
7
7
´ _ 2
3.1358
Possible root.
))
2.0000
-07
Negligible stress.
Beame's beam has zero shear stress at
approximately 3.1358 meters and an
abrupt change of stress at 10.0000 meters.
When no root is found and Error 8 is displayed, you can press − or any
one key to clear the display and observe the estimate at which the function
was closest to zero. By also reviewing the numbers in the Y- and Z-
registers, you can often determine the nature of the function near the root
estimate and use this information constructively.