$\"\"$

The total cost for $\"\"$ units is $\"\"$ .

Find the order size which produces a minimum cost.

$\"\"$

Apply derivative with respect to $\"\"$ .

$\"\"$

Find the relative extremas by equating the first derivative to zero.

$\"\"$

So tthe order size which produces a minimum cost is $\"\"$ units.

$\"\"$

Tthe order size which produces a minimum cost is $\"\"$ units.