Big symbol "|" in latex

Question

I need to use | with the mean of "such that". It's in an expression with fraction and so I need to have a big |. I've tried to use \displaystyle before | but it doesn't work. Putting \left before | work, but Texstudio give an error because there isn't any \right. What can I do?

you can always size it with an wxplicit size. \bigg might be appropriate. — barbara beeton, Jun 20 '18 at 18:26
Please accept an answer if you have found a solution. By the way, I would recommend zyy's answer, as this will scale with the content! — nox, Jun 20 '18 at 19:12

score 12 · Answer 1 · answered Jun 20 '18 at 19:13

I find the ‘middle’ commands look better for this:

\documentclass{article}

\usepackage{mathtools}

\begin{document}
    \[
\left.\frac{\partial f(x, y)}{\partial x}\right| f(t) = t^2 + 1
 \]%
    \[
 \frac{\partial f( x, y)}{\partial x}\biggm| f(t) = t^2 + 1
 \]%

\end{document}

zyy · Accepted Answer · 2020-11-10T15:16:56.913

4

You could do the following

\begin{equation}
\left. \frac{\partial f \left( x , y \right)}{\partial x} \right|_{x = 0}
\end{equation}

This will yield

edited Nov 10 '20 at 15:16

answered Jun 20 '18 at 18:25

zyy

2,146

1

What's the purpose of writing f \left( x , y \right) instead of, say, f(x,y)? Put differently, why make (La)TeX insert whitespace between f and (? – Mico Jun 20 '18 at 20:45
@Mico LaTeX just recognize \left( \right) as occupying more space, I kind of have the habit of using \left( \right) instead of ( ) for all situation so that my document is more consistent. – zyy Jun 20 '18 at 21:08
1

"...so that my document is more consistent." You know what Ralph Waldo Emerson had to say about consistency, right? If not, here goes: "A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines. With consistency a great soul has simply nothing to do. He may as well concern himself with his shadow on the wall." (excerpt from an essay, entitled "Self-Reliance") Ouch! :-) – Mico Jun 22 '18 at 08:14
@Mico Hey! It does take me some effort to make sense of this quote! It is true that we should think out of the box, but it is also not bad to keep some idea while you not yet getting a new one! – zyy Jun 23 '18 at 17:32
2

In case you're still not convinced that using \left and \right for the sake of consistency is maybe not all that great an idea, do check out the posting Is it ever bad to use \left and \right? – Mico Jun 23 '18 at 17:33
1

@Mico Yeah, that makes sense. – zyy Jun 28 '18 at 14:47

score 4 · Answer 3 · answered Jun 20 '18 at 18:37

4

If you want only a left delimiter but not a right one, you can use \left| \right. (with a dot).

answered Jun 20 '18 at 18:37

Bart Michels

1,298
2
13
24

Sebastiano · Answer 4 · 2020-11-10T21:52:45.667

Using a specific package called diffcoeff (https://ctan.mirror.garr.it/mirrors/ctan/macros/latex/contrib/diffcoeff/diffcoeff.pdf) you can obtain the same result. It is not a classic command but it is very simple to understand. The \diffdef{pvrule}{op-symbol=\partial} is a macro for to write a partial symbol.

\documentclass[a4paper,12pt]{article}
\usepackage{diffcoeff}
\diffdef{pvrule}{op-symbol=\partial}
\begin{document}
[\diff.pvrule.{f(x,y)}x[x=0]]
\end{document}

Addendum:

You can use a similar code for the function of one variable using the character $d$ : see the macro op-symbol=d.

\documentclass[a4paper,12pt]{article}
\usepackage{diffcoeff}
\diffdef{pvrule}{op-symbol=d}
\begin{document}
[\diff.pvrule.{(x^2+3x)}x[x=1]=5]
\end{document}

Big symbol "|" in latex

4 Answers4

Addendum: