null function

How does the null function work ? When I row-reduce as a method of finding eigenvectors, I sometimes get a very different answer from what the null function produces.

Answer 1

[Walter Roberson]

http://www.mathworks.com/help/techdoc/ref/null.html

Z = null(A) is an orthonormal basis for the null space of A obtained from the singular value decomposition. That is, A*Z has negligible elements, size(Z,2) is the nullity of A, and Z'*Z = I