I know the formula for continuous compounded interest with monthly payments/investment is this,
p = monthly payment i = interest per year c = compounded times per year t = times compounded FV = p((1+i/c)^t - 1) / (i/c)
But to have it start with an initial amount is what's puzzling me.
For example, I'd like to start with $1000, with a monthly payment/investment of $100 and monthly compounded interest of 8% annual (so 0.08/12 since it's monthly).
What is the formula to get this future value at t amount of times?