Linear Algebra

Let’s consider the matrix

>> A = {{1, 1, 0}, {1, 0, 1}, {0, 1, 1}};

The derivatives are

>> MatrixForm(A)

We can compute its eigenvalues and eigenvectors:

>> Eigenvalues(A)

>> Eigenvectors(A)

This yields the diagonalization of A:

>> T = Transpose(Eigenvectors(A)); MatrixForm(T)

>> Inverse(T) . A . T // MatrixForm

>> % == DiagonalMatrix(Eigenvalues(A))

We can solve linear systems:

>> LinearSolve(A, {1, 2, 3})

>> A . %

In this case, the solution is unique:

>> NullSpace(A)

Let’s consider a singular matrix:

>> B = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};

>> MatrixRank(B)

>> s = LinearSolve(B, {1, 2, 3})

>> NullSpace(B)

>> B . (RandomInteger(100) * %[[1]] + s)