Outline

  • is a matrix with rows and columns.
  • Matrices are equal if each of their corresponding entries are equal.
  • If , we have a square matrix.
  • Addition of matrices: just like vectors, corresponding entries are summed up.
  • Scalar multiplication of matrices: like vectors, each entry is multiplied with the scalar multiple.
  • Transpose of is . Rows become columns, and cols become rows.
  • Symmetric matrices. If . (not vice versa)