implementing what if parameter and calculating production decline

[umanbr]

Hi all,
I need to calculate decrease over years using the following script. How can I convert it to Dax?
----------
function decrease (p,n,r)
{
d=p
i=2 to (n)
P=p *(1-r)
Decrease =decrease +p
next i
end function
}.
thanks!

[v-danhe-msft]

Hi @umanbr ,

I could not understand the rate parameter. If function decline(10,5,rate), could it get a result of 80?

First decline=10,then 20(10+10) then40(20+20)....

Or it should be 50, first decline=10,then 20(10+10) then30(10+20)....

Could you please offer a desired result and  explain how it work for your formula?

Regards,

Daniel He