Numerical Analysis Questions & Answers  




There's some LATEX problems in your question formulation: you need to make sure the math is surrounded by \$ signs. Please post again below with correct typesetting.




This is a very good explanation. There is only a small problem with it: you should have written $B$ instead of $X$ within the last column. 3 points bonus boost.




Fixed. Good observation. 1 point bonus boost.




Well, try it. Calculate $(P_{23}M_{1}P_{12})^{1}$ and see if that is lower triangular.. If not, you answered your question.



$\pi$ 