So i have the following matrix:(adsbygoogle = window.adsbygoogle || []).push({});

A= [2,0,-1; 4,0,-2;0,0,0]

I do r-r-e

I get

[1,0,-1/2;0,0,0;0,0,0]

So my rank for A is 1, because I only have 1 leading one.

Now for my nullity, i get the following

x_1 - 1/2 X_3 = 0

-->

x_1=1/2 x_3

therefore

[x_1,X_2,X_3] =[1/2;0;1]t

Which would imply that nullity = 1

which then wouldn't satisfy the Dimension theorem for matrices..

which states

rank(a)+nullity(a) = n, where n is the # of columns.

..

so my question is.. what am I doing wrong?

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# Homework Help: Question about nullity and rank

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