The total cost C( x ) Rs associated with the production of x units is given by,
C( x )=0.007 x 3 −0.003 x 2 +15x+4000
Marginal cost is the rate of change of total cost with the output.
The marginal cost is MC.
According to the given condition,
MC= dC dx = d dx ( 0.007 x 3 −0.003 x 2 +15x+4000 ) =3×0.007 x 2 −2×0.003x+15 =0.021 x 2 −0.006x+15 (1)
Substitute the value of x as 17 in equation (1).
MC=0.021 ( 17 ) 2 −0.006( 17 )+15 =0.021×289−0.006×17+15 =6.069−0.102+15 =20.967
Thus, the marginal cost of 17 units produced is Rs 20.967.