Answer
3000 unit cost = $180,000$ dollar
additonal 200 unit cost = $6026.67$ dollar
Work Step by Step
3000 unit cost
= $\int_0^{3000}(120-0.06x+0.00001x^{2})dx$
= $(120x-0.03x^{2}+\frac{0.00001}{3}x^{3})|_0^{3000}$
= $180,000$ dollar
additonal 200 unit cost
= $\int_{3000}^{3200}(120-0.06x+0.00001x^{2})dx$
= $(120x-0.03x^{2}+\frac{0.00001}{3}x^{3})|_{3000}^{3200}$
= $6026.67$ dollar
