Re: A86: Confirm Calendar Bug..


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Re: A86: Confirm Calendar Bug..




TGaArdvark@aol.com wrote:

> > Should 2000 be 29 days or is it correct as 28?  If it is incorrect, then is
> > all 400x years [0,400,800,...] have 29 days whereas all other 100 years have
> > 28?   Can someone tell me for sure?  I will probably also add saving feature
> > in the next version... Thanks for any help.
>
> Since a year is 365.24 days, that adds 1 day every 4 years and subtracts
> one day every hundred (from the +1 every 4).  Therefore, every hundredth
> year is not a leap year.  I am probably wrong.

A year is actually 365 days, 5 hours, 48 minutes, and 46 seconds -- which comes
out to be 365.2421990741 days.

Take the years 1000 through 1999 inclusive.  That's 1000 years right?  If we
didn't account for leap year (365.00 days in a year), there would be 365000 days
in that time span.  If we considered every year divisible by 4 to be a leap year,
there would be 250 leap years in that time span for a total of 365250 days now.
Now if we say that the century years not divisble by 400 are NOT leap years (1000,
1100, 1300, 1400, 1500, 1700, 1800, 1900), we have 8 less days for a total of
365242.  This comes closer to the exact number of days there should be in that
time span which is 365.2421990741 * 1000 = 365242.1991.  So you see that in 1000
years, we have an extra .1991 of a day that we aren't accounting for.  So for
every ~5000 years we need an extra leap year in there, and who knows where that
falls.

--
Bryan Rabeler <brabeler@ticalc.org>
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