Lecture 2, Math 235 (W08)

Determinants Cont....(pdf file Sect 3.2 suppl. notes)

• Example with triangular and near triangular matrices (Theorem 2: If A is a triangular matrix, then det A is the product of the main diagonal entries of A.)
• Properties of Det e.g.
  • • adding a multiple of one row to another leaves the det. unchanged
    • if two rows are interchanged, the sign of det changes
    • if one row is multiplied by k, then det is multiplied by k
• Calculating det A using row reduction to triangular form (since det of a triangular matrix is given by the product of the diagonal entries)
• See Video numbers 18,19