Mathematics may be incorporated into the lines of text (‘inline’) or set off on its own lines (‘displayed’).
Inline:
We used Pythagoras’s theorem, \(a^2+b^2=c^2\), to find the long side of the triangle.
Displayed:
We used Pythagoras’s theorem,
\[a^2+b^2=c^2,\]
to find the long side of the triangle.
A mathematics text will usually use both inline and displayed equations:
- Use inline mathematics if the expression is simple and short, and does not need to be referred to later on.
- Use displayed mathematics if the expression is likely to have a line break in it, looks cramped, forces the lines of text apart or must be referred to later in the text (in which case it should be numbered; see Numbering equations).
Use different layouts for inline and displayed equations. Note the positions of the limits on the integral sign, for example:
| Inline |
Displayed |
| \( \int_0^1 f(x) dx = 3 \) |
\[ \int_0^1 f(x) dx = 3 \] |
| \(\sum_{i=0}^n a_i=1 \) |
\[\sum_{i=0}^n a_i=1 \] |
| \( \lim_{x \rightarrow \infty} f(x)=b \) |
\[ \lim_{x \rightarrow \infty} f(x)=b \] |
| \( \frac{x+y}{z} \) or (preferred if inline) \( (x+y)/z\) |
\[ \frac{x+y}{z} \] |
The exact style of expression (eg whether the displayed equations are centred, left-aligned or indented) is determined by the publication you are writing for.
Caution! Microsoft Word has a bug that causes it to set any equation that shares a line with non-equation text as if it is inline rather than displayed. Putting the punctuation inside the equation environment may help, but only if the equations are not numbered (see Punctuating equations).
Consider other tools for layout, such as MathType (which works with Word) or LaTeX (which is a Word alternative). (See Using LaTeX.)
