### 13.2. Preparing a formula with TeX

If you prefer to use Plain TeX, here is the same example in that notation.

% math.tex: Sample of TeX math for inclusion in DocBook
%
\hsize=6in
\nopagenumbers
$$\int \tanh^{-1}{x\over a}dx = x \tanh^{-1}{x\over a}+{a\over 2}\log(a^2-x^2),\qquad \left(\left| x\over a \right| < 1\right) \leqno{(14)}$$
\bye

• The line \hsize=6in sets the text column width to six inches.

• Because the production process wraps a box around whatever text is on the page, use \nopagenumbers to turn off page numbering.

• To place equation numbers on the left, use \leqno or \leqalignno.