Cost Function Analysis Using Polynomial Regression

00:00 10 marks

  • Build Confidence
  • SL
  • Tier 4
  • Differentiation
  • Rate of change
  • Marginal cost
  • Regression-based polynomial

A manufacturing company has collected cost data (in thousand dollars) based on production units (u) as follows:

– For 100 units, the cost is 60.
– For 200 units, the cost is 100.
– For 300 units, the cost is 180.

Using this data, answer the following:

(a) Determine a quadratic polynomial cost function of the form \(C(u)= au^2 + bu + c\) that fits the data.

(b) Differentiate the cost function you obtained to find the marginal cost function \(C'(u)\).

(c) Use the marginal cost function to estimate the approximate change in cost when production increases from 300 to 301 units.

Part a

4 minutes 3 marks

Question

Determine a quadratic polynomial cost function of the form \(C(u)= au^2 + bu + c\) that fits the following data:

\(u = 100,\; C(100)= 60\)
\(u = 200,\; C(200)= 100\)
\(u = 300,\; C(300)= 180\)



Hint Hint

Hint

Set up a system of equations for \(a\), \(b\), and \(c\) using the given data points.

  • Answer Answer

Complete Answer

\(a = 0.002,\; b = -0.2,\; c = 60\)

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Part b

4 minutes 3 marks

Question

Differentiate the cost function \(C(u)= 0.002u^2 – 0.2u + 60\) to find the marginal cost function \(C'(u)\).



Hint Hint

Hint

Differentiate each term using the power rule.

  • Answer Answer

Complete Answer

\(C'(u)= 0.004u – 0.2\)

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  • Answer Explanation Answer Explanation

Part c

4 minutes 4 marks

Question

Using the marginal cost function \(C'(u)= 0.004u – 0.2\), estimate the approximate change in cost when production increases from 300 to 301 units.



Hint Hint

Hint

Evaluate the derivative at \(u=300\) to approximate the cost increase per additional unit.

  • Answer Answer

Complete Answer

Approximately \(1.0\) (thousand dollars)

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