Faculty use

Defective Matrices and Jordan-Form Preview

Reward correct mathematics, explicit dimensions/hypotheses, interpretation, and verification. Equivalent valid reasoning should receive credit.

Problem 1

No; it has only one independent eigenvector for a 2-dimensional space.

Problem 2

A nilpotent superdiagonal part that produces polynomial factors multiplying λᵏ in powers.

Problem 3

Definitions should identify the vector/matrix/space/transformation, dimensions or domain/codomain, and the hypotheses behind recognizing when eigenvectors do not form a basis. Use the formulas defective if geometric multiplicity too small; A=PJP⁻¹ in Jordan form over a splitting field.

Problem 4

A strong error analysis identifies the first step that violates a definition, dimension, theorem hypothesis, or matrix-operation rule; then repairs that step and re-verifies the final result.

Problem 5

Application responses vary. Require defined variables, a compatible matrix/vector model connected to long-term dynamics, recurrence models, rotations, stability, vibration, and differential systems, a complete computation, interpretation, and limitations.

Problem 6

Accept two independent checks appropriate to the task: reconstruction, residual, RREF comparison, determinant/rank test, orthogonality, substitution, eigenpair check Av=λv, factorization product, or a second method.

Scoring guidance

Six problems × 10 points: 5 mathematical accuracy, 2 structure/justification, 2 verification/interpretation, 1 notation and communication.

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