If you've got 100 in A1, and you want to reduce to 96 over 4 quarters, try
=A1*(1-4%)^(1/4) and copy down.
I'm not sure of the relevance of your "area under a curve"?
--
David Biddulph

"Penfold1981" wrote in message
...
I'm trying to use Excel to work out some targets and I know I want a 4%
reduction over the year- i.e. I had 100 last year and want 96 this year,
so
how do I work out how many I need to record in each financial quarter to
make
that happen? It wouldn't be one per quarter because that would give me a
'flat-line' target and not a decreasing trajectory. Apparently there's a
formula, possibly something to do with integration and working out the
area
under a curve? Can anyone help??!