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-MFra-21-Topaz II
21-Topaz II
October 5, 2024
Question

Points instead of apex for the derivatives of a function.

  • October 5, 2024
  • 2 replies
  • 3410 views

Warm greetings to all,
I remember that a few years ago, a post was published asking how to write one or more points overlapping the function to be derived, instead of one or more apexes, but I can't find it, so how can I do it especially for MATHCAD 15? the difficulty lies in placing the dots on the functions, then we proceed with the prefix operators and the like.

Thank you very much.

2 replies

W
Werner_E25-Diamond I
25-Diamond I
October 5, 2024
how to write one or more points overlapping the function to be derived, instead of one or more apexes

???

Can you give an example or describe in more detail what you are talking about and what any prefix operator would have to do with it?

 

You are not talking about showing points on the graph of a function instead using just vertical markers, aren't you?

Werner_E_1-1728126462513.png

Or are you talking about Newton's dots-notation of a derivative?

Here you would have to use Windows's character map, group after Unicode and chose the section with diacritic characters.

Use U+0307 and U+0308 for one and two dots. Not sure  how to create higher derivatives (e.g. three dots in triangle shape on top of a variable name).

Werner_E_0-1728128376279.png

In languages where umlauts (ä,ö,ü) are used (German, Turkish, ...), the use of ü can be misleading. Equally if not more problematic is the Newton notation for the first derivative of a current function i(t).

The ISO-80000-2 does not address this issue and explicitly specifies the point notation only for the first and second derivative as permissible notation if the independent variable is time. I find this restriction to the meaning of the variable as time clearly too restrictive, because this notation is generally quite common for derivatives with parameter representation.

 

Maybe you have this thread   Re: Dot over variable - PTC Community   in mind or the thread(s) Luc is referring to?

 

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    -MFra-21-Topaz IIAuthor
    21-Topaz II
    October 5, 2024

    Sorry Werner, but I just wanted to reply but instead I clicked on accept solution. How do I uncheck "accept solution"?

    W
    Werner_E25-Diamond I
    25-Diamond I
    October 5, 2024
    @-MFra- wrote:

    Sorry Werner, but I just wanted to reply but instead I clicked on accept solution. How do I uncheck "accept solution"?

    Sorry, I don't know.

    But  once you selected a reply as being the solution you should be able to change your mind and select another one later as being solution. Valery has used this a lot in threads he started and which often ended up with one of his own follow up replies as being the solution 🙂

     

    S
    StuartBruff23-Emerald V
    23-Emerald V
    October 5, 2024

    Can you post a sketch of what you mean?

     

    Stuart

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    -MFra-21-Topaz IIAuthor
    21-Topaz II
    October 5, 2024

    insteadof.jpg

    S
    StuartBruff23-Emerald V
    23-Emerald V
    October 5, 2024

    Following on from Werner's comments, here's something (modified) from a Unicode worksheet that I wrote a few years ago.  It's in Mathcad Prime 10, but I think it should port to Mathcad 15.

     

    2024 10 05 D.png

     

    For those not familiar with diacritical characters, they effectively give an application's screen drawing code instructions to "backspace" over the preceding character and overstrike that character with the diacritical character.  Consequently, to delete the overstruck character entirely both the character and the diacritic must be deleted.

     

    In some rendition systems, diacritics can be combined; in the triple dot case shown above, this means deleting three characters to delete the overstruck character.  Diacritics can also be confusing when moving the cursor across a character - usually, two movements are required.

     

    NB: In Prime, To make use of a single- or double-dotted character, copy the string output, paste it into a Math Region, and delete the quotes.  To copy any of the overstruck characters to a TextBox,  copy it into the Find Box, deleted the quotes, and then copy/paste the overstruck character into the Text Box.

     

    Stuart

     

    The original Unicode worksheet was written in response to an Alfasoft article on this topic.  As usual, what started as a simple couple of lines of Mathcad code ended up as a multipage horror of intertwined functions as ideas and abstractions occurred to me. Unfortunately, this means the Unicode worksheet is quite complex and challenging to disentangle to give a short solution to the overstrike problem. Otherwise, I'd have posted the worksheet.

     

    1. https://support.alfasoft.com/hc/en-us/articles/360003722078-How-to-add-things-on-top-of-characters-used-as-variable-names

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