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# Template:Cases

The {{cases}} mathematical formatting template is used to typeset mathematical cases in either HTML+CSS or LaTeX. (In LaTeX, the cases environment is used for the definition of piecewise functions.)

## Usage

{{cases|begin}} or {{cases|begin|format}} or {{cases|begin|left brace size}} or {{cases|begin|left brace size|format}}
...
{{cases|end}} or {{cases|end|format}}

where

• first argument: begin or end;
• [optional] second argument (left brace size) (ignored by LaTeX, size automatically adjusted): big, Big, bigg or Bigg (default bigg);
• [optional] last argument (format): htm or tex (default htm).

If you want LaTeX style (using the {{begin}} and {{end}} templates):

{{begin|cases}} or {{begin|cases|format}} or {{begin|cases|left brace size}} or {{begin|cases|left brace size|format}}
...
{{end|cases}} or {{end|cases|format}}

## Examples

### Examples using {{cases}} template

The code

{{indent}}{{math|F{{sp|-2}}{{sub|''n''}}{{sp|1}}(''x'') {{sp}}{{sym|def}}{{sp}}
{{cases|begin}}
{{&}}0,{{&}}if ''n'' {{=}} 0, {{\\}}
{{&}}1,{{&}}if ''n'' {{=}} 1, {{\\}}
{{&}}F{{sp|-2}}{{sub|''n''{{sp|1}}{{op|-}}1}}{{sp|1}}(''x'') {{op|+}} ''x'' F{{sp|-2}}{{sub|''n''{{sp|1}}{{op|-}}2}}{{sp|1}}(''x''),{{sp|quad}}{{&}}if ''n'' {{rel|ge}} 2.
{{cases|end}}
|tex = {\rm F}_{n}(x) :=
{{cases|begin|tex}}
0, & \text{if } n = 0, \\
1, & \text{if } n = 1, \\
{\rm F}_{n-1}(x) + x \, {\rm F}_{n-2}(x), & \text{if } n \geq 2.
{{cases|end|tex}}
|&&}}


yields the display style HTML+CSS (with the && option):

Fn (x)  :=
 ⎧ ⎨ ⎩
 0, if n = 0, 1, if n = 1, Fn  − 1 (x) + x Fn  − 2 (x), if n ≥ 2.

or yields the display style LaTeX (with the $$ option): ${\displaystyle {\begin{array}{l}\displaystyle {{\rm {F}}_{n}(x):={\begin{cases}0,&{\text{if }}n=0,\\1,&{\text{if }}n=1,\\{\rm {F}}_{n-1}(x)+x\,{\rm {F}}_{n-2}(x),&{\text{if }}n\geq 2.\end{cases}}}\end{array}}}$ The code {{indent}}{{math|''c''{{sp|1}}(''n'') {{=|sp}} {{cases|begin|big}} 1 {{&}}if ''n'' {{=}} 0, {{\\}} 2{{^|{{sp|-1}}''n''{{sp|1}}{{op|-}}1}} {{sp|quad}}{{&}}if ''n'' {{rel|ge}} 1. {{cases|end}} |tex = c(n) = \begin{cases} 1 & \text{if } n = 0, \\ 2^{n-1} & \text{if } n \ge 1. \end{cases} |&&}}  yields the display style HTML+CSS (with the && option): c (n) =  ⎰ ⎱  1 if n = 0, 2 n − 1 if n ≥ 1. or yields the display style LaTeX (with the $$ option):

${\displaystyle {\begin{array}{l}\displaystyle {c(n)={\begin{cases}1&{\text{if }}n=0,\\2^{n-1}&{\text{if }}n\geq 1.\end{cases}}}\end{array}}}$

### Examples using {{begin}} and {{end}} templates

The code

{{indent}}{{math|F{{sp|-2}}{{sub|''n''}}{{sp|1}}(''x'') {{sp}}{{sym|def}}{{sp}}
{{begin|cases}}
{{&}}0,{{&}}if ''n'' {{=}} 0, {{\\}}
{{&}}1,{{&}}if ''n'' {{=}} 1, {{\\}}
{{&}}F{{sp|-2}}{{sub|''n''{{sp|1}}{{op|-}}1}}{{sp|1}}(''x'') {{op|+}} ''x'' F{{sp|-2}}{{sub|''n''{{sp|1}}{{op|-}}2}}{{sp|1}}(''x''),{{sp|quad}}{{&}}if ''n'' {{rel|ge}} 2.
{{end|cases}}
|tex = {\rm F}_{n}(x) :=
{{begin|cases|tex}}
0, & \text{if } n = 0, \\
1, & \text{if } n = 1, \\
{\rm F}_{n-1}(x) + x \, {\rm F}_{n-2}(x), & \text{if } n \geq 2.
{{end|cases|tex}}
|&&}}


yields the display style HTML+CSS (with the && option):

Fn (x)  :=
 ⎧ ⎨ ⎩
 0, if n = 0, 1, if n = 1, Fn  − 1 (x) + x Fn  − 2 (x), if n ≥ 2.

or yields the display style LaTeX (with the $$ option): ${\displaystyle {\begin{array}{l}\displaystyle {{\rm {F}}_{n}(x):={\begin{cases}0,&{\text{if }}n=0,\\1,&{\text{if }}n=1,\\{\rm {F}}_{n-1}(x)+x\,{\rm {F}}_{n-2}(x),&{\text{if }}n\geq 2.\end{cases}}}\end{array}}}$ The code {{indent}}{{math|''c''{{sp|1}}(''n'') {{=|sp}} {{begin|cases|big}} 1{{&}} if ''n'' {{=}} 0, {{\\}} 2{{^|{{sp|-1}}''n''{{sp|1}}{{op|-}}1}} {{sp|quad}}{{&}}if ''n'' {{rel|ge}} 1. {{end|cases}} |tex = c(n) = \begin{cases} 1 & \text{if } n = 0, \\ 2^{n-1} & \text{if } n \ge 1. \end{cases} |&&}}  yields the display style HTML+CSS (with the && option): c (n) =  ⎰ ⎱  1 if n = 0, 2 n − 1 if n ≥ 1. or yields the display style LaTeX (with the $$ option):

${\displaystyle {\begin{array}{l}\displaystyle {c(n)={\begin{cases}1&{\text{if }}n=0,\\2^{n-1}&{\text{if }}n\geq 1.\end{cases}}}\end{array}}}$

The code

{{indent}}{{math|sgn{{sp|1}}(''x'') {{sp}}{{rel|def}}{{sp}}
{{begin|cases|Big}}
0 {{&}}{{sp|quad}}{{text|if}} ''x'' {{=}} 0, {{\\}}
{{end|cases}}
|tex = \sgn(x) :=
\begin{cases}
\, 0 & \text{if } x = 0, \\
\frac{x}{ {{abs|x|tex}} } & \text{if } x \ne 0.
\end{cases}
|&&}}


yields the display style HTML+CSS (with the && option):

sgn (x)  :=
 ⎰ ⎱
0 if x = 0,
 x | x |
if x ≠ 0.

or yields the display style LaTeX (with the  option):

${\displaystyle {\begin{array}{l}\displaystyle {\operatorname {sgn}(x):={\begin{cases}\,0&{\text{if }}x=0,\\{\frac {x}{\vert x\vert }}&{\text{if }}x\neq 0.\end{cases}}}\end{array}}}$