In lecture 7, my understand that F is a two-row matrix, with the first row=[2 -2] and the second=[0 2]. Then R is defined as [[I F][0 ]]. And then, N=[[-F] [N]]. RN=0. So this should mean that R (the row-reduced echelon matrix) times N is the zero vector. But this doesn't work. I must be missing something obvious. For one thing, I (as presented in the video) is in cols 1 and 3, rows 1 and 2, and F is in cols 2 and 4, rows 1 and 2. They're "mixed" (which is something alluded to in the next index). So was this R=[[I F][0 0]] more of a generic example?

Question

In lecture 7, my understand that F is a two-row matrix, with the first row=[2 -2] and the second=[0 2].  Then R is defined as [[I F][0 ]].  And then, N=[[-F] [N]].  RN=0.  So this should mean that R (the row-reduced echelon matrix) times N is the zero vector.  But this doesn't work.  I must be missing something obvious.  For one thing, I (as presented in the video) is in cols 1 and 3, rows 1 and 2, and F is in cols 2 and 4, rows 1 and 2.  They're "mixed" (which is something alluded to in the next index).  So was this R=[[I F][0 0]] more of a generic example?

anonymous · Answer

N = [-F I ] '