Answer
Sample answer: $\mathrm{u}=\left[\begin{array}{l}
1\\
0
\end{array}\right]$, $c=2$
Work Step by Step
Sample answer:
$\mathrm{u}=\left[\begin{array}{l}
1\\
0
\end{array}\right]\in H$, because $1^{2}+0^{2} \leq 1.$
If c=2,
$c\mathrm{u}=\left[\begin{array}{l}
2\\
0
\end{array}\right]\not\in H$, because $2^{2}+0 > 1$
Another answer:
$u=\left[\begin{array}{l}
1\\
0
\end{array}\right]\in H, v=\left[\begin{array}{l}
0\\
1
\end{array}\right]\in H ,$
$u+v=\left[\begin{array}{l}
1\\
1
\end{array}\right]\not\in H$
