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Section 4: Problems

University-level exam questions for Computational Methods & Applications.

Norms and Conditioning

Problem 1.1

Compute ||A||₁, ||A||₂, and ||A||∞ for A = [[1, 2], [3, 4]].

Difficulty: Medium

Problem 1.2

Show that ||AB|| ≤ ||A|| ||B|| for any compatible matrix norm.

Difficulty: Medium

Problem 1.3

Compute the condition number κ₂(A) for A = [[1, 1], [1, 1+ε]] where ε is small.

Difficulty: Hard

Iterative Methods

Problem 2.1

Apply one iteration of Jacobi method to solve: 3x + y = 5 x + 2y = 5 starting from x₀ = [0, 0].

Difficulty: Easy

Problem 2.2

Prove that the Jacobi iteration for a strictly diagonally dominant matrix converges.

Difficulty: Very Hard

Eigenvalue Computation

Problem 3.1

Apply two iterations of the power method to A = [[2, 1], [1, 2]] starting with x₀ = [1, 0].

Difficulty: Medium

Problem 3.2

Explain why the power method fails for A = [[0, 1], [1, 0]].

Difficulty: Medium

Linear Programming

Problem 4.1

Solve using the simplex method: Maximize 3x + 4y Subject to: x + 2y ≤ 8, 3x + 2y ≤ 12, x,y ≥ 0

Difficulty: Hard

Problem 4.2

Write the dual of the LP in Problem 4.1 and verify strong duality.

Difficulty: Hard

Network Flow

Problem 5.1

Find the maximum flow in a network with given capacities.

Difficulty: Medium

Problem 5.2

Formulate the assignment problem as a linear program.

Difficulty: Medium

Game Theory

Problem 6.1

Find the optimal mixed strategies for the zero-sum game with payoff matrix: [[3, -1], [-2, 4]]

Difficulty: Hard

Problem 6.2

Formulate the game in Problem 6.1 as a linear program.

Difficulty: Very Hard

Challenge Problems

Problem 7.1

Prove the strong duality theorem for linear programming.

Difficulty: Very Hard

Problem 7.2

Implement the conjugate gradient method and analyze its convergence.

Difficulty: Very Hard


Solutions

Solutions are available in the implementation file with verification code.