Conversation started Jan 31, 2015 at 1:20.
usukidoll
usukidoll
Jan 31, 2015 01:20
so you need to find your main diagonal triangle like on a 3 x 3 matrix we have

1 2 3
3 3 3
3 3 9
Where 1 3 9 is the main diagonal triangle... do you see the numbers 3 3 and 3 the bottom left of the matrix? we need to get rid of them using row operations
now we need to follow some rules here... first and foremost we need a 1 on the top left
that 1 is supposed to go down and right like after I do the row operations I should get something like

1 2 3
0 1 3
0 0 1

or something like that
hmm there are 3 rules for echelon.. I can't remember one. but I know for reduce row wherever there is a 1 there must be a 0 in the column like the middle it must have 0 on the top and 0 on the bottom... basically for reduce row you are aiming for an identity matrix like this 3 x 3 example

1 0 0
0 1 0
0 0 1
bottom 1 must have all 0's on the top of the column...
let's see if I remembered correctly.... we have 3 row operations... we can switch the rows woo
we can add, subtract like r1-r2 -> r2 meaning subtract row one and row two and put the result in row 2
or you can multiply the row or divide the row.

like if I have

3 3 3 and I need to divide that first row... to get a one

1/3 r1 -> r1

1 1 1
similarly if I want 3's
3r1 -> r1
3 3 3
though a rule is broken already D: due to the fact that the top left MUST ALWAYS CONTAIN A ONE!
Note: Row operations are mostly used for matrices... there is only one type of matrix that allows column operations
and that's an elementary matrix
that is the only matrix that is allowed to do column operations.. everything else is pure row operations only
T Abraham
T Abraham
thanks..
T Abraham
T Abraham
Jan 31, 2015 02:03
@MarkMitchison u there?
@usukidoll wait, wat do u mean by echelon all the time?
usukidoll
usukidoll
huh?
most matrices are row operations only
T Abraham
T Abraham
Right now, I really need @alarge or @MarkMitchison ...
@usukidoll for example, chat.stackexchange.com/transcript/message/19818385#19818385
@usukidoll or chat.stackexchange.com/transcript/message/19818436#19818436
usukidoll
usukidoll
oh you mean the reduce echelon form rules yeah at first they are tricky to follow
T Abraham
T Abraham
@usukidoll no, I am asking, what is echelon?
usukidoll
usukidoll
Row echelon form
In linear algebra, a matrix is in echelon form if it has the shape resulting of a Gaussian elimination. Row echelon form means that Gaussian elimination has operated on the rows and column echelon form means that Gaussian elimination has operated on the columns. In other words, a matrix is in column echelon form if its transpose is in row echelon form. Therefore only row echelon forms are considered in the remainder of this article. The similar properties of column echelon form are easily deduced by transposing all the matrices. Specifically, a matrix is in row echelon form if All nonzero rows...
 
Conversation ended Jan 31, 2015 at 2:12.