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

-07Negligible 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.