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Re: AO-10 Keps



At 02:08 PM 11/15/98 -0800, B Keyport wrote:
>On Sun, 15 Nov 1998 11:27:36 -0800, Paul Williamson wrote:
>
>>Uh, no, I don't think so.  "0.0 e0" is an abbreviation for
>>0.0 X 10^0 (zero point zero times ten to the power zero),
>>which is equal to zero.  You might have to put the "e0"
>>back in for some programs, depending on how smart
>>they are about parsing this number.
>
>Algebra 101, here... Anything to the power 0, is equal to 1. Any proper
>calculator, or math professor, or anyone else that's got a math brain
>will inform you of that fact. 

True, but you're missing the point.

Elementary arithmetic, here ... 0.0 times anything is still zero.

Scientific notation like "X.YYY eZZ" means the value X.YYY
multiplied by the ZZ power of ten.  If X.YYY is zero, then it
doesn't matter what power of ten you multiply it by; ZZ
doesn't matter.  If ZZ is 0, then (as you say) the power of ten
part is equal to 1.  No matter, 0.0 times 1 is still zero.

The point is that "0.0 e0" is a perfectly valid way to express
a value of zero.  Some programs that read Keplerian elements
apparently get this wrong.  That's a bug in the program.

73  -Paul
kb5mu@amsat.org


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