Let A= [0] B=[1 2 3] C=[-3 7]
[-4] [0 5 2] [ 9 8]
[3] [0 0 1]
Find: 2AB, C+3A, (-B)^2
2AB is not defined because the only matrix products that are defined
is when the matrix on the left has the same number of columns and the
matrix on the right has rows. 2BA is defined, but not 2AB. Remember,
matrix multiplication is not commutative.
C+3A is also not defined because matrix addition is only defined when
the matrices to be added have the same dimensions.
(-B)^2 is defined
(-B)² = (-1·B)×(-1·B) = (-1)·(-1)·B×B = 1·B×B = B×B =
Edwin
