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Line notation for Geometry course

PostPosted: Thu Dec 05, 2019 7:45 pm
by anjutama
Hello, I am a math teacher and I need to write proofs with line names, which is AB with a two-sided arrow on top. I can't find a way to do it. There are instructions how to write AB with an arrow on top, but that it a vector or a ray, but not a line. Thank you!

Re: Line notation for Geometry course

PostPosted: Thu Dec 05, 2019 8:03 pm
by MrProgrammer
Hi, and welcome to the forum.

anjutama wrote:I need to write proofs with line names, which is AB with a two-sided arrow on top.
I will guess that you are asking about the Math feature of OpenOffice (File → New → Formula). Sorry, but I don't see a two-sided arrow in the list of formats. If this is a requirement, perhaps other software will better meet your needs. Writer (File → New → Text Document) also provides various overline styles, but none are a two-sided arrow.

Re: Line notation for Geometry course

PostPosted: Thu Dec 05, 2019 8:10 pm
by John_Ha
Format > Character > Font effects adds a line.

Clipboard03.gif

Look at the Math package of AOO or LO. File > New > Formula.

Windows allows you to write mathematical formulae with Start > Accessories > Math Input Panel.

Clipboard05.gif

Google for maths fonts. Latex is excellent for math formulae. There are on-line sites for math formulae like Online Mathematics Formula Editor

Showing that a problem has been solved helps others searching so, if your problem is now solved, please view your first post in this thread and click the Edit button (top right in the post) and add [Solved] in front of the subject.

Re: Line notation for Geometry course

PostPosted: Thu Dec 05, 2019 10:07 pm
by Lupp
(Off topic)

I'm also a math teacher (Germany), now retired for more than a decade, but I cannot remember to often have read mathematical texts containing the notation for straight (unlimited) lines you described. Starting with texts (transcribed) from ancient Greece lines defined by two points were denoted by simply putting the two one-letter-point-names side by side. As an example "AB x BC = B if A, B, C not are collinear" should tell the obvious. (When I wrote a paper where I wanted to denote the operation of joining two given points A and B by a straight line g explicitly I used "A..B = g".)

Where and since when is the notation described in the question common or even mandatory?

Re: Line notation for Geometry course

PostPosted: Fri Dec 06, 2019 6:00 pm
by anjutama
@Lupp Different notations are used in Europe and America. In the USA, the line is denoted by a double-sided arrow above, and a line segment by a line above. Since I write this for school aged kids, I need to keep the notations as they are used in the textbooks here.

Re: Line notation for Geometry course

PostPosted: Fri Dec 06, 2019 8:12 pm
by John_Ha
John_Ha wrote:Latex is excellent for math formulae.

... and the add-on amsmath supports double-headed arrows. See Typesetting arrows above a pair of letters to indicate a line

Clipboard01.gif

The brute force and ignorance AOO method is to use the Draw component of Writer to add the arrows or create an image of arrows and add it above the letters.