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Archiver > GENEALOGY-DNA > 2006-04 > 1146380268


From: "Jason S. Clary" <>
Subject: Re: [DNA] Exponentiation
Date: Sat, 29 Apr 2006 23:57:48 -0700
References: <380-22006403053036237@earthlink.net>


It's the same either way. 1/(2^4) = (1/2)^4

The former is easier to calculate if you want a fraction result because it
yeilds a partial solution of 1/16 as opposed to .0625 which is, as it
happens, 1 divided by 16. The order of operations doesn't matter between
division and multiplication.

I'd guess 1/156 was a typo... missed the backspace? ;P

Careful with the term exp, it's used to mean something else and yeilds
entirely different results. Normally 2exp4 would be 2*10^4 or 20,000 which
is obviously not the same thing. This is what is meant by e+ numbers on a
calculator when you exceed the display capabilities so 2exp4 is also the
same as 2.e+4 which is 20000. The order of operations is important with the
exp function as it yeilds entirely different results depending on how you do
it. 1/(2exp4)=1/20000=0.00005 and (1/2)exp4=5000.

The function is pow in languages that don't use ^ for powers. pow() is a
two parameter function so it would be written pow(1/2, 4) or 1/pow(2,4)
which as I said give the same result either way.




----- Original Message -----
From: "Eric Olson" <>
To: <>
Sent: Saturday, April 29, 2006 10:30 PM
Subject: RE: [DNA] Exponentiation


> Thank you John,
>
> It's good to be on the same page... It's still awkward notation though
> isn't it? I'd be inclined to write that expression as (1/2)^4 for
> clarity,
> or (1/2)exp4, or even as 1/(2exp4) if that is your meaning. Yet that
> equals 1/16, not 1/156? 1/2 to the fourth power is 1/2 x 1/2 x 1/2 x 1/2
> ... no? Please explain how it equals 1/156 in a computer language .....
>
> Cheers,
> Eric
>
>
>> [Original Message]
>> From: John Lerch <>
>> To: <>
>> Date: 4/29/2006 9:55:35 PM
>> Subject: [DNA] Exponentiation
>>
>> Eric asked what I meant by "^". It's the expresssion in several
>> computer languages for exponentiation. So
>> 1/2^4 neabs 1/2 to the fourth power or 1/156
>> JAL
>>
>>
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