$\"\"$

\

The equation is $\"\"$ .

\

Substitute $\"\"$ .

\

$\"\"$

\

Substitute resistance $\"\"$ , capacitance $\"\"$ , constant voltage $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Apply integral on each side.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

The initial charge is $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

Substitute $\"\"$ in $\"\"$ .

\

$\"\"$

\

The charge is $\"\"$ .

\

$\"\"$

\

$\"\"$

\

Apply derivative on each side with respect to $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Substitute $\"\"$ .

\

The current is $\"\"$ .

\

$\"\"$

\

$\"\"$ .

\

$\"\"$ .