# Thread: Show something is a subspace..

1. ## Show something is a subspace..

Show that U intersect W is a subspace of U union W is a subspace of U+W. I have no idea where to start!

2. $U\cap W=U\cup W\ ?$

3. Originally Posted by cookiesyum
Show that U intersect W is a subspace of U union W is a subspace of U+W. I have no idea where to start!
$U\cap W$ is not always a subspace!