View source for Math 3.x formula layout

The most difficult part of using OOo Math comes when writing complicated formulas. This section provides some advice.

== Brackets are your friends ==
OOo Math knows nothing about order of operation. You must use brackets to state order of operations explicitly. Consider the following example:

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>2 over  x + 1</tt>||<math>{2 \over x} + 1</math>
|-
|<tt>2 over {x + 1}</tt>||<math>2 \over {x + 1}</math>
|-
|}

== Equations over more than one line ==
Suppose you want to type an equation covering more than one line. For example: 

<math>x = 3\,\!</math>

<math>y = 1\,\!</math>

Your first reaction would be to simply press the ''Enter'' key. However, if you press the ''Enter'' key, though the markup goes to a new line, the resulting equation does not. You must type the newline command explicitly. This is illustrated in the table below.

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>x = 3</tt><br/><tt>y = 1</tt>||<math>x = 3 \ y = 1</math>
|-
|<tt>x = 3 newline</tt><br/><tt>y = 1</tt>||<math>x = 3\,\!</math>
<math>y = 1\,\!</math>
|-
|}

== How do I add limits to my sum/integral? ==
The sum and int commands can (optionally) take in the parameters ''from'' and ''to''. These are used for lower and upper limits respectively. These parameters can be used singly or together. Limits for integrals are usually treated as subscripts and superscripts.

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>sum from k = 1 to n a_k</tt><br/>||<math>\sum_{k=1}^n a_k</math>
|-
|<tt>int from 0 to x f(t) dt</tt><br/>or <br/><tt>int_0^x f(t) dt</tt>||<math>\int\limits_0^x f(t) dt</math> or <math>\int_0^x f(t) dt</math>
|-
|<tt>int from Re f</tt>||<math>\int\limits_\Re f</math>
|-
|<tt>sum to infinity 2^{-n}</tt>||<math>\sum_{ }^{\infin} 2^{-n}</math>
|-
|}

{{Documentation/Note|For more details on integrals and sums, see [[Documentation/OOo3_User_Guides/Writer_Guide/Math_commands_reference|Math commands- Reference]] in the Writer Guide.}}

== Brackets with matrices look ugly! ==
For background, we start with an overview of the matrix command:

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>matrix { a # b ## c # d }</tt>||<math>\begin{matrix} a&b \\ c&d \end{matrix}</math>
|-
|}

{{Documentation/Note|Rows are separated by two #'s and entries within each row are separated by one #.}}

The first problem people have with matrices is that brackets do not scale with the matrix:

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>(  matrix { a # b ## c # d }  ) </tt>||(<math>\begin{matrix} a&b \\ c&d \end{matrix}</math>)
|-
|}

OOoMath provides scalable brackets. That is, the brackets grow in size to match the size of their contents. Use the commands ''left('' and ''right)'' to make scalable brackets.

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>left(  matrix { a # b ## c # d }  right)</tt>||<math>\left( \begin{matrix} a&b \\ c&d \end{matrix} \right)</math>

|-
|}

{{Documentation/Tip|Use ''left['' and ''right]'' to obtain square brackets.}}

== How do I make a derivative? ==
Making derivatives essentially comes down to one trick: ''Tell OOo it's a fraction''.

In other words, you have to use the ''over'' command. Combine this with either the letter ''d'' (for a total derivative) or the ''partial'' command (for a partial derivative) to achieve the effect of a derivative.

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>{df} over {dx}</tt>||<math>\frac{df}{dx}</math>
|-
|<tt>{partial f} over {partial y}</tt>||<math>\frac{\partial f}{\partial y}</math>
|-
|<tt>{partial^2 f} over {partial t^2}</tt>||<math>\frac{\partial^2 f}{\partial t^2}</math>
|-
|}

{{Documentation/Note|Notice that we have to use braces (squiggly brackets) to make the derivative.}}

==How do I align my equations at the equals sign?==
OOo Math does not have a command for aligning equations on a particular character, but you can use a matrix to do this, as shown below.

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Markup!!Result
|-
|<tt>matrix{<br/>  alignr x+y # {}={} # alignl 2 ##<br/>  alignr x   # {}={} # alignl 2-y<br/>}</tt>||[[Image:005a.gif]]
|-
|}

The empty braces around = are necessary because = is a binary operator and thus needs an expression on each side.

You can reduce the spacing around = if you change the inter-column spacing of the matrix:

# With the equation editor open, choose '''Format > Spacing''' from the menu bar.
# In the Spacing dialog, click the '''Category''' button and select '''Matrices''' in the drop-down menu.
# Enter '''0%''' for Column spacing and click '''OK'''.

[[Image:MathMatrixSpacing.png|thumb|none|500px|Changing spacing in a matrix formula]] 

{{Documentation/SeeAlso| 
* [[Documentation/FAQ/Formula/How_do_I_align_my_equations_at_the_equality_sign%3F | How do I Align my Equations at the Equality Sign?]] 
}}
[[Category:Math]]