# MathJaxUsing large or 'big' parentheses

#### Peter

##### Well-known member
MHB Site Helper
In some expressions like $$\displaystyle f(g(x))$$ , especially complex ones, it may be helpful to use large or 'big' parentheses ... for example for the first and last parentheses in the given expression above.

Can someone help with the correct Latex for this?

Peter

#### MarkFL

Staff member
I use the \left and \right commands. For example the code:

\left(\frac{x^2}{3y^2-2} \right)^2

produces:

$$\displaystyle \left(\frac{x^2}{3y^2-2} \right)^2$$

You can use them with other brackets (right-click to see the codes used)

$$\displaystyle \left\lfloor \frac{\sqrt{x}}{2} \right\rfloor$$

$$\displaystyle \left.\frac{dy}{dx} \right|_{x=3}$$

$$\displaystyle \left\langle \cos^2(t),\sin(t)-\frac{t}{3} \right\rangle$$

#### Peter

##### Well-known member
MHB Site Helper
I use the \left and \right commands. For example the code:

\left(\frac{x^2}{3y^2-2} \right)^2

produces:

$$\displaystyle \left(\frac{x^2}{3y^2-2} \right)^2$$

You can use them with other brackets (right-click to see the codes used)

$$\displaystyle \left\lfloor \frac{\sqrt{x}}{2} \right\rfloor$$

$$\displaystyle \left.\frac{dy}{dx} \right|_{x=3}$$

$$\displaystyle \left\langle \cos^2(t),\sin(t)-\frac{t}{3} \right\rangle$$
Thanks Mark, appreciate the help ...

I tried

f \left( g(x) \right)

and got

$$\displaystyle f \left( g(x) \right)$$

but I wanted the parentheses around the g(x) to be larger ... in some cases I would want them considerably larger ... than the parentheses around the x - which, alas, as you can see did not happen

Can you help further ... what am I missing?

#### Opalg

##### MHB Oldtimer
Staff member
I tried

f \left( g(x) \right)

and got

$$\displaystyle f \left( g(x) \right)$$

but I wanted the parentheses around the g(x) to be larger ... in some cases I would want them considerably larger ... than the parentheses around the x - which, alas, as you can see did not happen

Can you help further ... what am I missing?
You can specify the size manually if you do not like the results given by \left and \right. The commands (for increasing sizes) are \bigl, \Bigl, \biggl and \Biggl, with corresponding commands on the right (\bigr etc.). The results (starting with a regular size parenthesis) look like $(\ \bigl( \ \Bigl( \ \biggl( \ \Biggl($.

I always use the \bigl and \bigr commands for expressions like the one you want: $f\bigl(g(x)\bigr).$

#### Peter

##### Well-known member
MHB Site Helper
You can specify the size manually if you do not like the results given by \left and \right. The commands (for increasing sizes) are \bigl, \Bigl, \biggl and \Biggl, with corresponding commands on the right (\bigr etc.). The results (starting with a regular size parenthesis) look like $(\ \bigl( \ \Bigl( \ \biggl( \ \Biggl($.

I always use the \bigl and \bigr commands for expressions like the one you want: $f\bigl(g(x)\bigr).$

Peter

#### MarkFL

Staff member
Thanks Mark, appreciate the help ...

I tried

f \left( g(x) \right)

and got

$$\displaystyle f \left( g(x) \right)$$

but I wanted the parentheses around the g(x) to be larger ... in some cases I would want them considerably larger ... than the parentheses around the x - which, alas, as you can see did not happen

Can you help further ... what am I missing?
The left and right commands only make the bracketing symbols as "tall" as the expressions they are enclosing...but I also learned some new commands from Opalg.

#### Ackbach

##### Indicium Physicus
Staff member
Also just a note about \left and \right: I find that when combined with exponents, $\LaTeX$ tends to put it too far to the right. So you can use two \! commands to reduce that spacing. Compare
$$\left( \frac{45}{x-3} \right)^{2} \quad \text{with} \quad \left( \frac{45}{x-3} \right)^{ \! \!2} \quad \text{or even, with one \!, } \left( \frac{45}{x-3} \right)^{ \! 2}.$$

#### dwsmith

##### Well-known member
There are a few more advantages of the big over left and right.
1. If you want to have just a right, you have to \left. and then \right| whereas with big you can just do \big|
2. If you are using an align environment, and you want a \left one side of the ampersand =, you need to then do a phantom to have equal hieght spacing on the right sides and you need \right. and a \left. Again, the use of \big( doesn't cause this issue

#### Peter

##### Well-known member
MHB Site Helper
There are a few more advantages of the big over left and right.
1. If you want to have just a right, you have to \left. and then \right| whereas with big you can just do \big|
2. If you are using an align environment, and you want a \left one side of the ampersand =, you need to then do a phantom to have equal hieght spacing on the right sides and you need \right. and a \left. Again, the use of \big( doesn't cause this issue

Can someone help me with the Latex code to obtain a large { and a large }?

I have tried the following but it does not seem to work:

\Biggl{ \Biggr}

Help would be appreciated.

Peter

#### MarkFL

Staff member
Can someone help me with the Latex code to obtain a large { and a large }?

I have tried the following but it does not seem to work:

\Biggl{ \Biggr}

Help would be appreciated.

Peter
You need to "escape" the brackets by preceding them with a backslash:

\Biggl\{ \Biggr\}

produces:

$$\displaystyle \Biggl\{ \Biggr\}$$

#### dwsmith

##### Well-known member
Can someone help me with the Latex code to obtain a large { and a large }?

I have tried the following but it does not seem to work:

\Biggl{ \Biggr}

Help would be appreciated.

Peter
What you are trying to do is render an escape character. The escape characters are: \ % ${ & # ~ ^. These render with \%, \$, \{, \&, \#. You can render \ with either \_ or \textbackslash. ~ can be render with \sim or \textasciitilde. Lastly, ^ is rendered with \textasciicircum

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