[Tutor] Little problem with math module

Tiago Katcipis katcipis at inf.ufsc.br
Mon Apr 21 03:40:11 CEST 2008


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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