negative base raised to fractional exponent
sjmachin at lexicon.net
Wed Oct 17 00:26:02 CEST 2007
On Oct 17, 8:03 am, Steve Holden <st... at holdenweb.com> wrote:
> schaefer... at gmail.com wrote:
> > Does anyone know of an approximation to raising a negative base to a
> > fractional exponent? For example, (-3)^-4.11111 since this cannot be
> > computed without using imaginary numbers. Any help is appreciated.
> A couple of questions.
> 1. How do you approximate a complex number in the reals? That doesn't
> make sense.
> 2. x ^ -4.1111 = 1 / (x ^ 4.1111), so where do complex numbers enter
> into this anyway?
> 3. I think you will find the complex numbers start to emerge as you
> explore fractional exponents.
This is part of the story -- the other part is that the story differs
depending on whether x is positive or negative.
> This being Python, and an interactive interpreter being available, you
> can always just try it:
> >>> -3 ** -4.1111
Steve, Trying to memorise the operator precedence table for each of
several languages was never a good idea. I admit advanced age :-) and
give up and use parentheses, just like the OP did:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: negative number cannot be raised to a fractional power
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