\tdplotsetmaincoords{77}{-8}%
\begin{tikzpicture}[tdplot_main_coords]
		x={(2 cm, 2 cm)},%
		y={(2 cm, 2 cm)},%
		z={(2 cm, 2 cm)}%
	]%
	\draw [->] (0,0,0) -- (1,0,0) node[below] {$x_1$};%
	\draw [->] (0,0,0) -- (0,0,1) node[left] {$x_2$};%
	\draw [->] (0,0,0) -- (0,1,0) node[left] {$x_3$};%
\end{tikzpicture}%