S= A + A^2 + A^3 +.... A^(B-1) + A^B
S/A =1 + A + A^2 + A^3 +.... A^(B-1)
(1 - 1/A)*S=A^B - 1
S= A*(A^B -1)/(A-1)
This is the formula you are after. It is frequently used in financial interest
calculations. Not sure where it comes into sundial design.
Regards
Chris Lusby Taylor
-----Original Message-----
From: Tad Dunne [SMTP:[EMAIL PROTECTED]
Sent: 18 September 1998 20:41
To: Sundial List
Subject: What's sum of series of increasing powers?
Help!
I'm working on an Excel spreadsheet and need a formula or function that
will give,
for an input A and B, the sum of all the powers of A for integers from
1 to B.
Example: 1.05 + 1.05 squared + 1.05 cubed ...
Can anyone help me?
-- Tad Dunne
