The align environment provided by AMS-LaTeX is used for two or more equations when vertical alignment is desired; usually equal signs are aligned. Use ampersands (&) for alignment and a double backslash (\\) to insert a linebreak.

## Example

 Markup \begin{align} x-1 &= y \\ x &= y+1 \end{align}  Renders as {\displaystyle \begin{align} x-1 &= y \\ x &= y+1 \end{align}}

It is even possible to use multiple alignment characters (&) per line:

 Markup \begin{align} x-1 &= y & a &= b+c \\ x &= y+1 & a-c &= b \end{align}  Renders as {\displaystyle \begin{align} x-1 &= y & a &= b+c \\ x &= y+1 & a-c &= b \end{align}}
 Markup \begin{align} \frac{d}{dx} \ln x &= \lim_{h\to 0} \frac{\ln(x+h) - \ln x}{h} \\ &= \ln e^{1/x} &&\text{How this follows is left as an exercise.}\\ &= \frac{1}{x} &&\text{Using the definition of ln as inverse function} \end{align}  Renders as {\displaystyle \begin{align} \frac{d}{dx} \ln x &= \lim_{h\to 0} \frac{\ln(x+h) - \ln x}{h} \\ &= \ln e^{1/x} &&\text{How this follows is left as an exercise.}\\ &= \frac{1}{x} &&\text{Using the definition of ln as inverse function} \end{align}}

## Preamble

To use align, import the amsmath package in your preamble with \usepackage{amsmath}.