Matrices, Vectors: Addition and Scalar Multiplication

type in a 2 X 2 matrix:

a={{1,2},{3,4}}

MatrixForm[a]

or use the Insert/Matrix memu:

a1=(({{0, 1}, {2, 3}}))

type in a 3 X 3 matrix:

b={{4,6,9},{6,0,-2},{5,-8,1}}

MatrixForm[b]

Dimensions[b]

v1 = {-2,5,0.8,0,1}

Dimensions[v1]

MatrixForm[v1]

v2 = {{4},{0},{7}}

Dimensions[v2]

MatrixForm[v2]

Addition of Matrices

A={{-4,6,3},{0,1,2}}

B={{5,-1,0},{3,1,0}}

MatrixForm[A]

MatrixForm[B]

A+B

MatrixForm[%]

A={{2.7,-1.8},{0,0.9},{9.0,-4.5}}

MatrixForm[A]

MatrixForm[-A]

MatrixForm[10/9 A]

MatrixForm[ 0 A]