[Tutor] Little problem with math module
Tiago Katcipis
katcipis at inf.ufsc.br
Mon Apr 21 05:42:13 CEST 2008
well i made a mistake again :P. i have the function x ^ 1/3, i first
remembered that negative numbers do not have a square, but in this case
negative numbers are ok...because it aint 1/2 ...its 1/3. Can anyone
give a hint of how i can calculate it without using pow ou **? none of
them work properly
Tiago Katcipis escreveu:
> im not understanding why is this a problem...i have this simple function
>
> def newton_divergente(x):
> return math.pow(x, 1.0/3.0)
>
> but when x = -20 it returns this error
>
> return math.pow(x, 1.0/3.0)
> ValueError: math domain error
>
> but why is that? is it impossible to calculate -20 ^ (1/3) ?
>
> here on my calculator i get the result -6,666666667, but python seens to
> dont now the answer, why? am i doing something wrong? =/
>
> thanks to everyone who tries do help
>
> best regards
>
> katcipis
>
>
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