Topic explanation

Standard explanation

(A+B)_ij = a_ij+b_ij. Commutative: A+B=B+A. Associative: (A+B)+C=A+(B+C). A+O=A.

Key points

• entrywise
• same size to add
• kA multiplies every entry
• size first
• ADD AND SUBTRACT: (A+B)ij = aij+b_ij. Commutative: A+B=B+A. Associative: (A+B)+C=A+(B+C). A+O=A.
• ADD AND SUBTRACT: (A+B)_ij = a_ij+b_ij.
• WHAT — ADD AND SUBTRACT: (A+B)ij = aij+b_ij. Commutative: A+B=B+A. Associative: (A+B)+C=A+(B+C). A+O=A.
• WHY — Why it matters: This rule is a separate learning unit inside addition and scalar multiply. It can be defined, applie

Labelled diagram