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I will write a lot about Euclidean Geometry the next time. This means I need to denote angles.

The symbol we use in class looks like \sphericalangle, but I've just seen that there is an \angle symbol / command:

enter image description here

Now I have three questions:

  1. What is the semantic difference of those three symbols? (And maybe other symbols you know for angles)
  2. \measuredangle is quite long and I don't think that I will need more than one symbol for angles (it depends on your answer to question 1). So I would like to re-define \angle so that I get the symbol of \measuredangle. I think the way to do this would be

    \renewcommand{\angle}{\measuredangle}
    

is that correct? When I do this, is there any way to get the original symbol of \angle?

(Not part of my main question, but I hope to get some comments about this: Is it a bad idea to use another symbol than \angle? How well-known is the difference of those symbols? (I know this is open, I just want to read what you think about it. I think semantics are important).)

closed as off-topic by egreg, barbara beeton, Tobi, dustin, Svend Tveskæg Oct 12 '14 at 15:24

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not fall within the scope of TeX, LaTeX or related typesetting systems as defined in the help center." – egreg, barbara beeton, Tobi, dustin, Svend Tveskæg
If this question can be reworded to fit the rules in the help center, please edit the question.

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    To answer your last question: let\OldAngle\angle and then \let\angle\measuredangle should do the trick. Then you can access the original \angle as \OldAngle. – Peter Grill Jan 16 '14 at 16:52
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    +1 to Peter, and the other questions are not really LaTeX-related (in my opinion). – masu Jan 16 '14 at 17:31
  • @SándorKazi: I think my question if there are more symbols for angles is LaTeX-related. Also, the question about the semantic difference. And the question if it's a bad idea to use another symbol than \angle ... well, I'll put that in brakets. This was not my main question. – Martin Thoma Jan 16 '14 at 17:34
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    The semantic difference is more likely a question of mathematical notation. I think the "is there more" is the same. One might use the letter "x" as an "angle symbol", this IS a question of what is common or what is not. Your question is good, but I think it's about general mathematics, not LaTeX. – masu Jan 16 '14 at 17:50
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    I would submit a "what notations are common" question on math.SX. You can also ask all your questions there. If you finally find the most suitable notation, then it can be a LaTeX question how to make it appear (if it's not one of the above). – masu Jan 16 '14 at 18:46
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[Answer for 1] I have a guess for your first question, but I think it is a reasonable guess.

\sphericalangle AOB = angle between two intersecting arcs on a sphere, specifically the angle between the two planes containing the arcs [There seems to be a distinction in notation where the center letter is O, not B]

\measuredangle ABC = the actual measured angle between points A and C at point B

\angle ABC = angle between points A and C at point B (the middle letter is the vertex) [I have also seen this used to define angles in Euclidean triangles].

[Answer for 2] You could use \newcommand instead of \renewcommand and define your own new command that is shorter but distinct (e.g., \mangle).

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