Topic explanation

Standard explanation

Signs + - + on the first row. Pick a row with zeros if you can. Minor = leftover 2x2. Sum a{ij} C{ij} along the chosen row.

Key points

• (-1)^i+j
• 2x2: ad-bc
• 3x3: cofactor expansion
• chessboard signs
• 3X3 COFACTORS: Signs + - + on the first row. Pick a row with zeros if you can. Minor = leftover 2x2. Sum a{ij} C{
• 3x3 COFACTORS: Signs + - + on the first row.
• WHAT — 3X3 COFACTORS: Signs + - + on the first row. Pick a row with zeros if you can. Minor = leftover 2x2. Sum a{ij} C{
• WHY — Why it matters: This rule is a separate learning unit inside determinants 2x2 and 3x3. It can be defined, applied, a

Labelled diagram