# Request for Hyperbolic $\sech \,x$ inclusion in MathJax

MathJax does not work for hyperbolic $$\sech \,x$$... Can it be now included? Thanks in advance.

EDIT1:

From user1729's comment suggestion, they work okay:

$$\operatorname{sech}(x)$$

$$\DeclareMathOperator{\sech}{sech}$$

$$\sech (y)$$

• Do you know that you can define it manually? \operatorname{sech}(x) renders as $\operatorname{sech}(x)$. – user1729 Jan 15 at 9:40
• Also, you can use \DeclareMathOperator{\sech}{sech}$\DeclareMathOperator{\sech}{sech}$ to define it everywhere in your post. So typing sech(x) now gives $\sech(x)$. (There is a way, or used to be a way, to define commands for a whole page, but I can't remember it at the moment.) – user1729 Jan 15 at 9:44
• $\csch$ doesn't work either, but $\coth$ does. It's not just Mathjax: those commands aren't in Latex either. – Peter Phipps Jan 15 at 11:48
• Thanks. First one works, but the second one ( *Declare..) does n't seem to. May be all hyperbolic functions and their inverses should be made readily available without user definition. – Narasimham Jan 15 at 16:20
• This answer mentions various way to define things locally (in one post) - using \DeclarMathOperator, \newcommand, \def, \let. @user1729 The scope of a macro is now only a single post (or a single comment) and not the entire page - this was changed in January 2019, the change was announced in this answer. – Martin Sleziak Jan 15 at 16:51
• \DeclareMathOperator should work, in the sense that it worked above for me... – user1729 Jan 15 at 16:51
• @Martin Thanks for the links. It's good that the scope was changed; it's silly otherwise (as the links demonstrate!). – user1729 Jan 15 at 16:53
• @1729 both work, may be was some error. – Narasimham Jan 15 at 17:16

Firstly, you can define it manually, so \operatorname{sech}(x) renders as $$\operatorname{sech}(x)$$. A more fancy way is to put \DeclareMathOperator{\sech}{sech} somewhere in your post, and then \sech will work everywhere in the post.
For example, I'll declare the operator (invisibly) here: $$\DeclareMathOperator{\sech}{sech}$$
And it renders nicely here: $$\sech(x)$$
(One way not to do it is to use \mathrm{csch} rather than \operatorname{csch}. For example, \operatorname{csch}x $$\operatorname{csch}x$$ is correctly spaced while \mathrm{csch} $$\mathrm{csch}x$$ is not. See here for more details.)