Matrices

• 2x2 matrix times 1x1 matrix = 1x1 matrix
• 2x2 matrix times 2x2 matrix = 2x2 matrix
• 1x1 matrix times a scalar = 1x1 matrix
• 2x2 times a scalar = 2x2 matrix
• Identity Matrix

  ( 1 0 )

  ( 0 1 )