I have a series which I want to have N terms, starting with term A, of which the sum is 1, and have a constant ratio, R between the terms.
Where I wanted R to be the square root of 15
To calculate this, I used
A = 1 / (1 + R(1 + R(1 + R)))
I've labelled it Geometric as that's the closest name I've found, but for the formula, this seems to be the inverse, where the sum is known, but the ratio is not, and the series is finite. What's the proper name for this series, and is there a formula that can calculate the first term (or mth term)?