Bug 149885 - Equation Editor (Math tool) needs explanation for adding exponents that are non-alpha or non-numeric
Summary: Equation Editor (Math tool) needs explanation for adding exponents that are ...
Status: RESOLVED WORKSFORME
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Documentation (show other bugs)
Version:
(earliest affected)
7.3.0.3 release
Hardware: All All
: medium enhancement
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-07-06 23:49 UTC by Richard England
Modified: 2022-07-07 16:52 UTC (History)
2 users (show)

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Description Richard England 2022-07-06 23:49:53 UTC
Description:
When creating an equation for Writer using the Math tool, it was required to add a "-" (minus sign) as a free standing exponent. Not as a negative value, just a lone minus sign.  An example can be created using the following limit equation as an example:

  lim from{x %tendto 6 sup -{} } { frac 2 (x-6)sup 3 }

Note the "6 sup -{}". The empty {} is required or the equation editor will expect a value, like -x or -5 or some unary operator. The {} appeases the robot and allows the free standing "-" to appear.  (The meaning is the limit as x approaches 6 from the negative side.)

An hour long search and trial and error session by two people was required before we stumbled on this solution.  It might save the next person at least that long to figure this out. 

Steps to Reproduce:
1. See description



Actual Results:
error occurs when a stand alone - is attempted

Expected Results:
description of using non-numeric non-alpha characters should be available


Reproducible: Always


User Profile Reset: No



Additional Info:
n/a
Comment 1 Rafael Lima 2022-07-07 00:43:24 UTC
Indeed the minus operator is unary and using it requires the curly brackets as you mentioned.

Alternatively, you could have entered the minus sign as text:

lim from{x %tendto 6 sup "-" } { frac 2 (x-6)sup 3 }

Or with an em dash
lim from{x %tendto 6 sup "—" } { frac 2 (x-6)sup 3 }

Or using a unicode symbol (here en dash)
lim from{x %tendto 6 sup %Ux2013 } { frac 2 (x-6)sup 3 }
Comment 2 Mike Kaganski 2022-07-07 05:53:20 UTC
(In reply to Richard England from comment #0)
> Expected Results:
> description of using non-numeric non-alpha characters should be available

One opens LibreOffice help [1], clicks on "Formulas (Math)" in Contents (to the right), "General Information and Usert Interface Usage" (the first sub-item), and "Welcome to the LibreOffice Math Help" - i.e., simply opens the very first Math help page. The page basically gives you some links to the following reading - and the very first link is: "Instructions for Using LibreOffice Math", under which there is "Entering Text" [2]. Quoting it:

> How to enter direct text strings that do not get interpreted?
> Some text strings get interpreted as operators automatically. Sometimes this is
> not what you want. If you want to write W* (a letter with a superscripted
> asterisk), the asterisk will be interpreted as a multiplication operator.
> Enclose the direct text within double quotes or add spaceholders.

Beyond the help (available at F1 keypress), there is also Documentation page [3] available on the LibreOffice website, where you can find Math Guide [4] with discussion of topics like "Unpaired brackets", "Formulas over multiple lines", "Markup language characters as normal characters" and other not-straightforward and corner cases.

There's also FAQ [5], with topics like "How do I get * as a superscript? Using x^* produces an error" [6] and "How do I use a keyword like in as a variable name" [7].

And then, there is https://ask.libreoffice.org/, with already answered questions like "In equation mode, how to use - sign in the superscript" [8], appearing as the first result for search like "math minus superscript".

Is this bug solved?

[1] https://help.libreoffice.org/
[2] https://help.libreoffice.org/7.3/en-US/text/smath/guide/text.html?&DbPAR=MATH
[3] https://documentation.libreoffice.org/en/english-documentation/
[4] https://documentation.libreoffice.org/assets/Uploads/Documentation/en/MG72/MG72-MathGuide.pdf
[5] https://wiki.documentfoundation.org/Faq/Math
[6] https://wiki.documentfoundation.org/Faq/Math/002
[7] https://wiki.documentfoundation.org/Faq/Math/106
[8] https://ask.libreoffice.org/t/in-equation-mode-how-to-use-sign-in-the-superscript/55682
Comment 3 Richard England 2022-07-07 16:52:30 UTC
Apparently my search ability, or perhaps my lack of familiarity with terms used in Libreoffice, kept me from finding these obvious hints/clues.

I consider this obviously well documented and closed.

Sorry for the wasted bandwidth and thank you for the very complete response.