Lazy

For the lazy, who dont want to construct everything again and again… Better copy the source.

Vectors

V=
\left( \begin{array}{c}
x\ y\ z\\end{array} \right)

Matrices

Id_{3} =
\left(
\begin{array}{ccc}
1 & 0 & 0 \ 0 & 1 & 0 \ 0 & 0 & 1 \\end{array}
\right)

Id_{4} =
\left(
\begin{array}{cccc}
1 & 0 & 0 & 0 \ 0 & 1 & 0 & 0 \ 0 & 0 & 1 & 0 \ 0 & 0 & 0 & 1 \\end{array}
\right)