when does a sqaure matrix have an inverse?
if the determinant of that matrix is non zero
how is the inverse of a matrix defined?
A^-1*A=I, where I is the identity matrix
what is the transpose of a matrix?
matrix where rows are columns of the original
what is a matrix if its transpose is equal to the original?
symmetric and sqaure
what is an eigenvalue and eigenvector?
an eigenvector v and a eigenvector lambda obeys the eqn Av=lambda*v
how do you find the eigenvalues?
det(A-lambda*I)=0
properties of eigenvalues
eigenvalues of A inverse are the inverse of the eigenvalues of A
eigenvalues of A^2 are the square of the eigenvalues of A
eigenvalues of A and A transpose are the same, but not the same eigenvectors
what is the trace of a matrix?
refers to the sum of the diagonal entries of that matrix
how to check if eigenvalues are correct?
compare the sum to the trace, should be equal
what is a vector norm??
a measure of the magnitude of the vector