[Tex/LaTex] Good typesetting practice for long equations

best practicesequationsmath-modetypography

I have the following (quite horrible) equation in my thesis:

\begin{align*}
\frac{\partial^2}{\partial t_1^2} f(t_0,t_1) = 
( \delta+2t_0+2t_1)^{\alpha( w-t_0+t_1 )-1} \cdot \bigl(  
\frac{\partial^2}{\partial t_1^2}\alpha(w-t_0+t_1) \cdot ( \delta+2t_0+2t_1) \cdot  \log ( \delta+2t_0+2t_1) +\\
\alpha'(w-t_0+t_1) \cdot 2 \cdot  \log ( \delta+2t_0+2t_1)+
\alpha'(w-t_0+t_1) \cdot ( \delta+2t_0+2t_1) \cdot  \frac{2}{\delta+2t_0+2t_1} +\\
2 \frac{\partial}{\partial t_1} \alpha( w-t_0+t_1 ) \bigr) +
( \delta+2t_0+2t_1)^{\alpha( w-t_0+t_1 )-2}\cdot\\
 \bigl( \frac{\partial}{\partial t_1} \alpha(w-t_0+t_1) \cdot ( \delta+2t_0+2t_1) \cdot \log ( \delta+2t_0+2t_1) + (\alpha (w-t_0+t_1) -2) \bigr) \cdot \\
\bigl( \alpha'(w -t_0+t_1) \cdot ( \delta+2t_0+2t_1) \cdot  \log ( \delta+2t_0+2t_1) +
2\alpha( w-t_0+t_1)\bigr) = \\
( \delta+2t_0+2t_1)^{\alpha( w-t_0+t_1 )-1} \cdot \Bigl( 
 \frac{\partial^2}{\partial t_1^2}\alpha(w -t_0+t_1) \cdot ( \delta+2t_0+2t_1) \cdot  \log ( \delta+2t_0+2t_1) +\\
2 \cdot \alpha'(w-t_0+t_1)  \cdot  \bigl( 2 + \log ( \delta+2t_0+2t_1) \bigr) \Bigr) +
( \delta+2t_0+2t_1)^{\alpha( w-t_0+t_1)-2} \cdot \Bigl( \\
\alpha '(w-t_0+t_1) \cdot 
(\delta + 2t_0+2t_1) \cdot \log (\delta + 2t_0+2t_1) +  
\bigl(\alpha (w-t_0+t_1) -2) \bigr) \cdot
 \bigl(   \\
\alpha'(w-t_0+t_1) \cdot ( \delta+2t_0+2t_1) \cdot  \log ( \delta+2t_0+2t_1) +2\alpha( w-t_0+t_1)\bigr) \Bigr)  < 0
\end{align*}

Using this exact piece of code, without any special formatting commands such as & or \[2mm] the resulting mathematical text is quite unreadable:
The equation

How would you format such equations in LaTeX and what would you say is good practice when typesetting such large equations?

Best Answer

I'd try to make the equation smaller by grouping parts:

  • Don't use \cdot where it's not necessary. I use it only for scalar products of vectors and for numbers, but not for symbolic factors or before parentheses.
  • Derivatives are often written as \partial_{t_1} instead of \frac{\partial}{\partial t_1}. This can save some space.
  • Introducing substitutions can be helpful. In your code (\delta+2t_0+2t_1) appears quite often and it could be replaced by a new symbol which will be defined before or after the equation
  • Align the equation at least on all equal signs: &=
  • Other line breaks may be before + signs to "group" summands (this shows that the equation consists of similar parts that are added together)