Question

Would anybody know how to row reduce this 4x4 matrix to prove it is linearly dependant? Needs all zeros accross bottom row.

[1,2,-1,4 ; 0,1,0,-1 ; 1,3,-1,1 ; -2,-4,2,-1]

Answer 1

\begin{array}c
1&2&-1&4 \\
0&1&0&-1 \\
1&3&-1&1 \\
-2&-4&2&-1\\
\end{array}

id try to use the rows above to reduce it

Answer 2

2(12-14)

2 4 -28
-2-42-1
--------
0 0 0 7

Answer 3

try to get the other rows into rref as well maybe

Answer 4

-1,-2,1,-4
1 ,3,-1, 1
----------
0 1 0 -3

1,2,-1,4 ; 0,1,0,-1 ; 0,1,0,-3 ; 0,0,0,7

1,2,-1,4
0,-2,0,2
--------
1,0,-1,6

1,0,-1,6; 0,1,0,-1 ; 0,1,0,-3 ; 0,0,0,7

0,-1,0,1
0,1,0,-3
---------
0,0,0,-2

1,0,-1,6; 0,1,0,-1 ; 0,0,0,-2 ; 0,0,0,7

hmmm

Answer 5

i kept running into dead ends as well thanks for helping hope you can get it

Answer 6

\begin{array}c
1&0&-1&6 \\
0&1&0&-1 \\
0&0&0&-2 \\
0&0&0&7\\
\end{array}

hmmmm

Answer 7

did the matrix come from a bigger probelm?

Answer 8

no that was the form it was presented in.

Answer 9

I don't remember much, but doesn't the matrix's determinant tell you something about linear dependence?

Answer 10

yeah just thought it would be easier this way.