how to bold all fraction lines like in the picture below? I used


but nothing happened.

enter image description here


1 Answer 1


Based on the answer of user David Carlisle from this question.


\usepackage{mathtools} % also loads the amsmath package

% Command with 2 obligatory arguments (num and denom)

% Command with 2 obligatory arguments (num and denom) and one optional argument (line width)





\myVariableThickFrac{\text{num}}{\text{demom}} = \myVariableThickFrac[3pt]{\text{num}}{\text{demom}} = \myVariableThickFrac[5pt]{\text{num}}{\text{demom}}


enter image description here

Question to the experts here. I don't know why the line width also influences the spacing so much. And I do not know that to do with the remaining arguments {left-delim}, {right-delim} and {mathstyle} (but that is not important here as it seems).

  • \genfrac is from the very famous amsmath package.
  • The package mathtools that I use here is an extension package to amsmath
  • mathtools loads amsmath automatically.
  • See mathtools vs amsmath for more details.

From the amsmath manual

enter image description here

  • The other statement (about mathtools) is not quite right. mathtools loads amsmath and provides additions to it. Nothing in this example needs mathtools, amsmath is enough
    – daleif
    Apr 6, 2017 at 11:14
  • 1
    I was simplifying on purpose. And I wanted to encourage to use mathtools :). I'll update the answer -- feel free to correct me again. Apr 6, 2017 at 11:15
  • @daleif I updated the answer and added another question :(. Maybe you can jump in. Apr 6, 2017 at 11:24
  • Me again, I just figure it that all lines are bold lines of box, all fraction lines, equal signs are also little bit bold, not bold with /textbf but bolder than mine. Does anyone has solution for that? :)
    – Ana Leko
    Apr 6, 2017 at 12:24
  • 1
    the width of the fraction lines is a parameter in the font dimensions (in .tfm files). it is a misfeature in tex that the space above and below the fraction line uses the same dimension parameter. this is a side effect of the very limited memory available when tex was created, and it's too late to change now.if .tfm files are being used for fonts. i don't know whether the limitation has been addressed in xetex or luatex. Apr 6, 2017 at 13:45

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