\begin{tikzpicture}[scale=1]
  \draw [thick, black, ->] (-2,0) -- (4, 0);
  \draw [thick, red, ->] (0,0) -- (0.866,0.5)
  node [right, black] {$u_1$};
  \draw [thick, black, ->] (0,-0.1) -- (0, 3);
  \draw [thick, red, ->] (0,0) -- (0.5, 0.866)
  node [left, black] {$u_2$};
  \draw [thick, red, ->] (0,0) -- (2,2);
  \draw (1.5,2)
  node [above] {$
      z = \left[ \begin{array}{c}
          z_1 \\
          z_2
        \end{array} \right]
    $};
\end{tikzpicture}
