Question

I am trying to align the following equations around the equal sign. What can I do? Thanks! I am using the AMSMath package

    $$m\ddot{x}_{1}-K(x_{2}+x_{12})+C(\dot{x}_{12}+\dot{x}_{2})+2C\dot{x}_{1} = fx_{1}$$
$$m\ddot{x}_{2}-K(x_{3}+x_{1})+C(\dot{x}_{1}+\dot{x}_{3})+2C\dot{x}_{2} = fx_{2}$$ 
$$m\ddot{x}_{3}-K(x_{4}+x_{2})+C(\dot{x}_{2}+\dot{x}_{4})+2C\dot{x}_{3} = fx_{3}$$ 
Was it helpful?

Solution

\begin{align}
    m\ddot{x}_{1}-K(x_{2}+x_{12})+C(\dot{x}_{12}+\dot{x}_{2})+2C\dot{x}_{1} &= fx_{1} \\
    m\ddot{x}_{2}-K(x_{3}+x_{1})+C(\dot{x}_{1}+\dot{x}_{3})+2C\dot{x}_{2} &= fx_{2} \\
    m\ddot{x}_{3}-K(x_{4}+x_{2})+C(\dot{x}_{2}+\dot{x}_{4})+2C\dot{x}_{3} &= fx_{3}
\end{align}

See the user's guide.

OTHER TIPS

To make a long story short... the following idea of using eqnarray is kind of obvious, but turns out to be a really bad idea. eqnarray brings lots of issues which are solved in amsmath and related packages. Read Lars Madsen: Avoid eqnarray for the details.

\begin{eqnarray*} %% Do avoid eqnarray if possible.
    x_1 & = & 1 \\
    x_2 & = & 2 \\
    x_3 & = & 3
\end{eqnarray*}

(Answer revised with information from Arthur Reutenauer, Thomas and the Madsen paper linked to by Thomas.)

There are several packages to do what you want, one of the most widely used is the AMS' align environment from the amsmath package.

Simplified extract from amsldoc.pdf:

\begin{align} 
x&=y \\ 
x’&=y’ \\ 
x+x’&=y+y’ 
\end{align}

The equations are aligned around the symbols that follow & (the equals signs, in this case).

Licensed under: CC-BY-SA with attribution
Not affiliated with StackOverflow
scroll top