Tutorial Week 3

Unbounded Regions

Q1: Find the minimal value of \(Z =x+3y\) given the constraints \(\begin{cases} 2x+4y\ge6 \\ 5x+y\ge5 \\ x, y \ge 0 \end{cases}\).

Q2: Is there a maximal value for the above function \(Z\)?

Numbers of Solutions

Q3: For the above question, if \(Z = x + 2y\), how many solutions would there be?

Matrices

Q4: Evaluate the following.

  1. \(-3 \cdot \begin{bmatrix} 3 & 0 \\ 2 & 1 \end{bmatrix}\)

\(\rule{0pt}{4ex}\) 2. \(\begin{bmatrix} 3 & 0 \\ 2 & 1 \end{bmatrix} + \begin{bmatrix} 1 & 5 \\ 3 & 4 \end{bmatrix}\)

\(\rule{0pt}{4ex}\) 3. \(\begin{bmatrix} 3 & 0 \\ 2 & 1 \end{bmatrix} \cdot \begin{bmatrix} 1 & 5 \\ 3 & 4 \end{bmatrix}\)?

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Q5: Find all diagonal matrices C such that \(\begin{bmatrix} 1 & 2 \\ 3 & 4 \end{bmatrix} = C^2 + \begin{bmatrix} -1 & 2 \\ 3 & 1 \end{bmatrix}\).

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Q6: Represent \(\begin{cases} 3x^3 + 7x^2 - x + 1 = 0 \\ 6x^2 + 5x = 0 \\ 12x^3 - x^2 + 9x + 1 = 0 \end{cases}\) as a matrix. Write this in the form of \(AX = B\), where \(A\) is the coefficient matrix, \(X\) is the variable matrix, and \(B\) is the solution matrix.

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