excel - How to return previous cell value after iterative change into a new cell -

typically, getting around using vba module since not programmer, think problem may require it. want create function or macro read "current" r^2 value off chart , dump value new cell called "previous" whenever data updates , r^2 value changes. in other words want excel file show both current active r^2 value chart , previous r^2 value before change 2 separate cells.

i using function =1-sumproduct((c3:c12-(d3:d12*index(linest(c3:c12,d3:d12,not(f$5)),1)+index(linest(c3:c12,d3:d12,not(f$5)),2)))^2)/sumproduct((c3:c12-average(c3:c12))^2) read active scatter plot , output r^2 value.

this closest result fine online: how old value of changed cell in excel vba?

image of workbook:

you need copy cell cell before updating graph.

'transfer current value previous value cell cells(11,7) = cells(10,7).value 'refresh sheet. (or whatever need update graph. application.calculate