achieve a million dollars in 30 years at 6% interest compounded continously
the formula for continuous compounding is the same as that for bacterial growth.
$\displaystyle P(t) = P_0 e^{rt}$
where $\displaystyle P(t)$ is the amount at time t, $\displaystyle P_0$ is the initial amount, $\displaystyle r$ is the rate of interest, and $\displaystyle t$ is the time.
you want to solve $\displaystyle 1000000 = P_0e^{0.06(30)}$ for $\displaystyle P_0$
the formula is usually written as $\displaystyle A = Pe^{rt}$ though. A is for amount, P is for principle