Problem 1
Their dot product is 2−2+0=0, so yes.
Faculty use
Inner Products and Orthogonality
Reward correct mathematics, explicit dimensions/hypotheses, interpretation, and verification. Equivalent valid reasoning should receive credit.
Problem 2
|⟨u,v⟩|≤‖u‖‖v‖, with equality exactly when u and v are linearly dependent.
Problem 3
Definitions should identify the vector/matrix/space/transformation, dimensions or domain/codomain, and the hypotheses behind generalizing dot-product geometry and proving inequalities. Use the formulas ⟨u,v⟩; u⊥v iff ⟨u,v⟩=0.
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 data fitting, approximation, signal decomposition, statistics, and numerical stability, 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.