Problem 1
Alternation plus multilinearity implies det(...,rᵢ,rⱼ,...)=−det(...,rⱼ,rᵢ,...).
Faculty use
Reward correct mathematics, explicit dimensions/hypotheses, interpretation, and verification. Equivalent valid reasoning should receive credit.
Alternation plus multilinearity implies det(...,rᵢ,rⱼ,...)=−det(...,rⱼ,rᵢ,...).
Scaling every one of n rows by c multiplies the determinant by c once per row, for a total factor cⁿ.
Definitions should identify the vector/matrix/space/transformation, dimensions or domain/codomain, and the hypotheses behind deriving determinant facts from defining properties. Use the formulas linear in each row separately; equal rows imply determinant 0.
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.
Application responses vary. Require defined variables, a compatible matrix/vector model connected to area and volume scaling, coordinate change, invertibility tests, and geometric design, a complete computation, interpretation, and limitations.
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.
Six problems × 10 points: 5 mathematical accuracy, 2 structure/justification, 2 verification/interpretation, 1 notation and communication.