$A\ =\ P\ \left(1\ -\ \frac{r}{n}\right)^{nt}$

$A\ =\ P\ \left(1\ +\ \frac{r}{n}\right)$

$A\ =\ P\ \left(1\ +\ \frac{1}{n}\right)^{nt}$

$A\ =\ P\ \left(\ 1\ +n\ \right)^{nt}$