# Left aligning centered equations

I have set of equations which I would like to just assign one number to. The equations should be aligned at the center of the page. The problem is that I would like all equations to begin at the same point whereas now they end at the same point. I use the \usepackage{amsmath}. Using the following input:

\begin{aligned} u_1 = \partial \phi_1 / \partial x + \partial \psi_1 / \partial z \\ w_1 = \partial \phi_1 / \partial z - \partial \psi_1 / \partial x \\ u_2 = \partial \phi_2 / \partial x \\ w_2 = \partial \phi_2 / \partial z \label{eq2.23} \end{aligned}


I get the following output:

The problem is that I want the u2 and w2 to appear directly below u1 and w1. If anyone can help me with this, I would greatly appreciate it!

• Or put & at the beginning of each row to align the left-hand edge. – Andrew Swann Dec 4 '15 at 9:31

Use the alignment tab & to justify the equations, i.e. substitute = by &=.
\documentclass{article}
\begin{aligned} u_1 &= \partial \phi_1 / \partial x + \partial \psi_1 / \partial z \\ w_1 &= \partial \phi_1 / \partial z - \partial \psi_1 / \partial x \\ u_2 &= \partial \phi_2 / \partial x \\ w_2 &= \partial \phi_2 / \partial z \label{eq2.23} \end{aligned}