Can Excael evaluate the expression, EXP(-X^2/(A*B)) accurately?

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

I have tried to evaluate the above expression in excel but i am not getting
the results I expected. I had to prefix a zero before the (-) sign before i
could get the desired results.

Is it because of some settings on my system or is it a bug? I am using Excel
2003 and it is supposed to be up to date.

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http://www.microsoft.com/office/com...73eb845&dg=microsoft.public.excel.crashesgpfs
 
See Help for "About calculation operators" subtopic "The order in which Excel
performs operations in formulas" Excel has always defined unary minus to
have higher priority than exponentiation. MS is unlikely to change that
since doing so would break any number of exisiting applications. Given that
documented order of precidence,
=EXP(-X^2/(A*B))
is interpreted as
=EXP((-X)^2/(A*B))
and evaluated correctly under that interpretation.

To get what you intended, you must either specifiy
=EXP(0-X^2/(A*B))
as you have noted, or
EXP(-(X^2)/(A*B))
to explicitly control the order of operations.

The caracterization of this group as "Excel Application Errors" in
Microsoft's Office Discussion Groups Home is easily misinterpreted. The
standard name of the group is microsoft.public.excel.crashesgpfs, and your
post has nothing to do with Excel crashing. You would have gotten an almost
immediate response had you posted the question in Worksheet Functions or
General Questions, where it would have been more on topic.

Jerry
 
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