Answer
Estimate = $0.244$
Actual = $0.244$
Work Step by Step
Estimate
$C'(x)$ = $0.25-1.5(\frac{x}{1000})^{2}(\frac{1}{1000})$ = $0.25-0.0015(\frac{x}{1000})^{2}$
$C'(2000)$ = $0.25-0.0015(\frac{2000}{1000})^{2}$ = $0.244$
Actual
$C(2000)$ = $300+(0.25\times2000)-0.5(\frac{2000}{1000})^{3}$ = $796$
$C(2001)$ = $300+(0.25\times2001)-0.5(\frac{2001}{1000})^{3}$ = $796.244$
$C(2001)-C(2000)$ = $796.244-796$ = $0.244$
