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MATH 01210 · Linear Algebra

MATH 01210 · Systems & matrices

Matrix operations

Definition

Add/subtract entrywise; scalar multiply; multiply AB when columns of A = rows of B. AB ≠ BA in general. Identity I satisfies AI=IA=A.

Read this

View AB as A acting on columns of B (linear transformation composition).

(AB)ᵀ=BᵀAᵀ. Trace and determinant have special properties under products.

Powers Aⁿ make sense for square matrices.

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Attempt each problem first, then open the worked solution.

  1. 1.Compute a 2×2 product and show a pair where AB≠BA.