[Tex/LaTex] Hyperbolic functions both produce error and result already existant when inserted in preamble

amsmathmath-operators

I'm trying to write hyperbolic functions like sech, csch, etc,

Since amsmath doesn't recognize them in the form \sech, \csch, …

I wrote a preamble like \DeclareMathOperator{\sech}{sech} but I get this error:

! LaTex Error: Command \tanh already defined. Or name \end... illegal, see p. 192 of the manual.

how should I write the hyperbolic functions?

Best Answer

not all the hyperbolic functions are defined in amsmath (actually, in amsopn.sty). only \sinh, \cosh, \tanh and \coth are defined there.

you can define the others exactly like you've shown for \sech, and can check in amsopn.sty if you encounter any other conflicts.

amsopn.sty was never meant to be exhaustive. it covers only the operator names found most frequently in ams publications as of the time it was compiled. there are surely many other possibilities.

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a better approach than embedding it in a center environment is to put it into a math display environment; either equation* or \[ ... \] will suffice.

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