HP 15C Uživatelský manuál stáhnout pdf (Strana 187)

Section 13: Finding the Roots of an Equation 187

Because the absolute-value function is minimum near an argument of zero,

specify the initial estimates in that region, for instance 1 and -1. Then

attempt to find a root.

Keystrokes

Display

| ¥

Run mode.

1 v

1.0000

Initial estimates.

1 “

–1

´ _ 1

Error 8

This display indicates that no

root was found.

−

0.0000

Clear error display.

As you can see, the HP-15C stopped seeking a root of f(x) = 0 when it

decided that none existed  at least not in the general range of x to which it

was initially directed. The Error 8 

operation has been attempted; it merely states that no root was found where

_ presumed one might exist (based on your initial estimates).

If the HP-15C stops seeking a root and displays an error message, one of

these three types of conditions has occurred:



If repeated iterations all produce a constant nonzero value for the

specified function, execution stops with the display Error 8.



If numerous samples indicate that the magnitude of the function

appears to have a nonzero minimum value in the area being

searched, execution stops with the display Error 8.



If an improper argument is used in a mathematical operation as part

of your subroutine, execution stops with the display Error 0.

In the case of a constant function value, the routine can see no indication of

a tendency for the value to move toward zero. This can occur for a function

whose first 10 significant digits are constant (such as when its graph levels

off at a nonzero horizontal asymptote) or for a function with a relatively

broad, locax-values being tried.

In the case where the function's magnitude reaches a nonzero minimum, the

routine has logically pursued a sequence of samples for which the

magnitude has been getting smaller. However, it has not found a value of

x at which the function's graph touches or crosses the x-axis.

1 2 ... 182 183 184 185 186 187 188 189 190 191 192 ... 287 288

Komentáře k této Příručce

Žádné komentáře

HP 15C Uživatelský manuál Strana 187

Komentáře k této Příručce