#

9.2 Displayed Mathematics

One-line unnumbered displayed mathematics can be created using:

where *<maths>* is the mathematics to be displayed.

**Example:**

Output:

`displaymath`environment or

`$$`

...`$$`

[15].
Use `\[`and

`\]`with the

`amsmath`package.

The `equation`
environment provides something similar to
`\[` `\]`, except
that the equation is numbered. Modifying the above example:

results in the following output:

which is provided by the `amsmath` package.

**Example:**

results in the following output:

[Re-using an equation]Recall from §5.5. Cross-Referencing that we can
cross-reference most things that LaTeX automatically numbers using `\ref`

and `\label`

.
Equations can be cross-referenced in the same way:

Equation numbers are usually given in parentheses, which can be done using:

The `amsmath` package provides a convenient short cut:

So the above can be written as:

**Note:**

Both the `equation` environment and
`\[`...`\]` are only designed for one
line of maths. Therefore you must not have any line breaks or
paragraph breaks within them.
The following will cause an error:

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