$\"\"$

The marginal cost is $\"\"$ .

Then the anti derivative of $\"\"$ is

$\"\"$

$\"\"$ , where $\"\"$ is a constant.

The cost of producing one item is $ $\"\"$ .

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

$\"\"$

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

$\"\"$ .

$\"\"$

Find the cost of producing $\"\"$ items.

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

$\"\"$

Therefore the cost of producing $\"\"$ items is $ $\"\"$ .

$\"\"$

The cost of producing $\"\"$ items is $ $\"\"$ .