Question $2\mathrm{.}6$: We cannot simply add these numbers to our balance$\_$array, as it would not include interest paid over the deposits. What we actually need is an array of the form

$[$P$,$

P $*$ factor $+$ A$,$

P $*$ factor$**2+$ A $*$ factor $+$ A$,$

P $*$ factor$**3+$ A $*$ factor$**2+$ A $*$ factor $+$ A$,...]=$

balance$\_$array $+$

$[0,$

A$,$

A $+$ A $*$ factor,

A $+$ A$*$ factor $+$ A $*$ factor$**2,$

A $+$ A$*$ factor $+$ A $*$ factor$**2+$ A $*$ factor$**3,...]$

Here we will produce this second array:

$[0,$

A$,$

A $+$ A $*$ factor,

A $+$ A$*$ factor $+$ A $*$ factor$**2,$

A $+$ A$*$ factor $+$ A $*$ factor$**2+$ A $*$ factor$**3,...].$

Let's start by producing

$[$A$,$ A $*$ factor, A $*$ factor$**2,...]$

with length equal to the total number of months minus $1.$ Save it in the variable A$\_$fac$\_$pwr below.

Hint: You can use the factors$\_$array again, but remove its last term.

A$\_$fac$\_$pwr $=...$

$$

A$\_$fac$\_$pwr