HP 15C Instrukcja Użytkownika Pobierz pdf (Strona 247)

Appendix E: A Detailed Look at f 247

format to i n or ^ n, where n is an integer,

implies that the



)(

10100.5)δ(

xmn

x 



)(

100.5

xmn



In this formula, n is the number of digits specified in the display format and

m(x) is the exponent of the function's value at x that would appear if the

value were displayed in i display format.

The uncertainty is proportional to the factor 10

m(x)

, which represents the

magnitude of the function's value at x. Therefore, i and ^ display

formats imply an uncertainty in the function that is relative to the function's

magnitude.

Similarly, if a function value is display in • n, the rounding of the

display implies that the uncertainty in the function's values is

.100.5)δ(





Since this uncertainty is independent of the function's magnitude, •

display format implies an uncertainty that is absolute.

Each time the f algorithm samples the function at a value of x, it also

derives a sample of (x), the uncertainty of the function's value at x. This is

calculated using the number of digits n currently specified in the display

format and (if the display format is set to i or ^) the magnitude

m(x) of the function's value at x     certainty of the

approximation to the desired integral, is the integral  (x):

Although i 8 or 9 generally results in the same display as i 7, it will result in a smaller

uncertainty of a calculated integral. (The same is true for the ^ format.) A negative value for n (which

can be set by using the Index register) will also affect the uncertainty of an f calculation. The minimum

value for n that will affect uncertainty is -6. A number in R

less than -6 will be interpreted as -6.

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HP 15C Instrukcja Użytkownika Strona 247