A fixed point is an in input to some function that is equal to the input.
$\huge f:x \mapsto x$
#### System for finding fixed points ([[Matrix|Matrix]] Transformations)
You can get an [[Augmented Matrix]] for finding the [[Fixed Points]] of a [[Matrix|Matrix]] by doing:
$\huge\begin{align*}
A \vec x &= \vec x \\
A\vec x - \vec x &= \vec 0 \\
\pa{A - I}\vec x &= \vec 0 \\
&\sim \augmented{c|c}{A-I & \vec 0}
\end{align*}$
>[!example]-
>$\huge T: \mat{x\\y} \mapsto \mat{3x-y\\4x-y}$
> Solve for $x, y$.
>$\huge\begin{align*}
\vec x &= \augmented{c|c}{A-I&\vec 0} \\
&\sim \augmented{cc|c}{2&-1&0\\4&-2&0} \\
&\sim \augmented{cc|c}{2&-1&0\\0&0&0} \\
&\sim \augmented{cc|c}{1& -\frac{1}{2} &0\\0&0&0} \\
&\sim\cases{ x - \frac{1}{2}y &= 0 \\ 0 &= 0 }
\end{align*}$