Monday, 6 May 2013

linear algebra - Does same characteristic polynomial and same rank imply similar?




Are two matrices with the same characteristic polynomial and the same rank necessarily similar? Where can I find the proof for such a thing?


Answer



The matrices



$$I=\left(\begin{matrix}1&0\\0&1\end{matrix}\right)\quad\text{and}\quad A=\left(\begin{matrix}1&1\\0&1\end{matrix}\right)$$
have the same characteristic polynomial $(x-1)^2$ and are both full rank but they are not similar since the identity matrix $I$ is only similar to itself.


No comments:

Post a Comment

real analysis - How to find $lim_{hrightarrow 0}frac{sin(ha)}{h}$

How to find $\lim_{h\rightarrow 0}\frac{\sin(ha)}{h}$ without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...