yogi_Compute Row By Row Sum Of Successive Rows In Column A Beginning With Row 2

                                          Google Spreadsheet   Post  #951

Yogi Anand, D.Eng, P.E.      ANAND Enterprises LLC -- Rochester Hills MI     www.energyefficientbuild.com.    Jan 02, 2013
user Fabio A.  said:(http://productforums.google.com/forum/?zx=cb22zc7h6wwc#!category-topic/docs/spreadsheets/7or0v2Kx3ys)

this situation (click to open up an image).

In the first column I have certain values, in the second column, given a certain row, I want it to contain the result of a function applied to all the preceeding rows (plus itself) in the 1st column. In this case the function applied is SUM().

The dumb approach is the one I used: write the formula in the first row, then copy&paste down till the row you want the function to be applied to.

I want it to be automated, though, and function with as many rows in the given column as there are, even if they are removed or added.  I thought I'd use ARRAYFORMULA() for this, or MMULT() combined with TRANSPOSE() as I've seen doing in apparently related examples, but after quite a few tries I'm lost.

Does anybody know how it can be done?

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following is a solution to the problem