How can I calculate my savings with varying deposits using the interest formula?

[Unassuming]

Homework Statement

Using the following savings formula, where d is a uniform deposit, i= (interest rate)/(# times compounded per year), n is the total times compounded.

As I understand it, this formula will tell me how much I will have after depositing a certain amount of money per compounding period given an interest rate and time.

How can I take into account the situation where I start off by depositing a large sum like $5000, and then make uniform deposit during every compounding period?

Homework Equations

I am using the savings formula,

$$A=d(\frac{(1+i)^n-1}{i})$$

The Attempt at a Solution

 

[HallsofIvy]

Use that formula one the first amount, the same formula, with the time one month less, on the amount deposited for the second month, the formula with the time two months less for the amount deposited on the third month, etc. and then add them all.