Re: rank question

[Tatsuro MATSUOKA]

Sorry for my confusing post.
I rewrite from the first. Please ignore the first two posts

>> A=[ 
1,2,3,4,5,6,7 
7,6,5,4,3,2,1 
9,10,11,12,13,14,15 
6,4,2,0,-2,-4,6 
10,12,14,16,18,20,22 
] 
A = 

    1    2    3    4    5    6    7 
    7    6    5    4    3    2    1 
    9   10   11   12   13   14   15 
    6    4    2    0   -2   -4    6 
   10   12   14   16   18   20   22 

>> rank(A) 
ans =  3 


The same results  are obtained on Scilab and Maxima. 

However, row basic deformations of A give to  

    1    2    3    4    5    6    7 
    0   -8  -16  -24  -32  -40  -48 
    0   -8  -16  -24  -32  -40  -48 
    0   -8  -16  -24  -32  -40  -48 
    0   -8  -16  -24  -32  -40  -48 

    1    2    3    4    5    6    7 
    0    1    2    3    4    5    6 
    0    0    0    0    0    0    0 
    0    0    0    0    0    0    0 
    0    0    0    0    0    0    0 

Is not the rank of A two (2)? 
Am I misled ? 


Tatsuro