What is this number called?












0














Sorry, pretty awful title to describe my question.



Sometimes I like playing around with series expansions for certain functions on Mathematica, and if the function has a singularity at a point $b$, sometimes the little suggestion box will say something like "Series around $ x=b$" and will give me a series expansion around that point. I know this number is special, I don't know why, but sometimes at that series expansion it will have the obvious singularity, like $dfrac{1}{x-b}$ and then after that a finite number followed by more powers of $x$ with coefficients.



What is that finite number called?










share|cite|improve this question
























  • What number?${}$
    – Git Gud
    Aug 11 '15 at 9:41










  • The coefficient of $(x-b)^0$? Is it the residue?
    – Empy2
    Aug 11 '15 at 9:45










  • I have an example: wolframalpha.com/input/?i=1%2F%28s*%28s%2B1%29%29 If you go to where it says Series expansion at s=0, it will give 1/s-1+s+.....i'm talking about the -1 in that series expansion. Its not always -1, and sometimes there is no constant term at a series expansion around a singularity, but is there a name for the constant term in a series expansion for a function around its singularity?
    – Dave huff
    Aug 11 '15 at 9:45










  • Don't you mean $(x-b)^{-1}$ ?
    – Yves Daoust
    Aug 11 '15 at 9:46










  • My bad on the description, its not a coefficient on any of the series terms, its a constant number, there is no x multiplying it.
    – Dave huff
    Aug 11 '15 at 9:47
















0














Sorry, pretty awful title to describe my question.



Sometimes I like playing around with series expansions for certain functions on Mathematica, and if the function has a singularity at a point $b$, sometimes the little suggestion box will say something like "Series around $ x=b$" and will give me a series expansion around that point. I know this number is special, I don't know why, but sometimes at that series expansion it will have the obvious singularity, like $dfrac{1}{x-b}$ and then after that a finite number followed by more powers of $x$ with coefficients.



What is that finite number called?










share|cite|improve this question
























  • What number?${}$
    – Git Gud
    Aug 11 '15 at 9:41










  • The coefficient of $(x-b)^0$? Is it the residue?
    – Empy2
    Aug 11 '15 at 9:45










  • I have an example: wolframalpha.com/input/?i=1%2F%28s*%28s%2B1%29%29 If you go to where it says Series expansion at s=0, it will give 1/s-1+s+.....i'm talking about the -1 in that series expansion. Its not always -1, and sometimes there is no constant term at a series expansion around a singularity, but is there a name for the constant term in a series expansion for a function around its singularity?
    – Dave huff
    Aug 11 '15 at 9:45










  • Don't you mean $(x-b)^{-1}$ ?
    – Yves Daoust
    Aug 11 '15 at 9:46










  • My bad on the description, its not a coefficient on any of the series terms, its a constant number, there is no x multiplying it.
    – Dave huff
    Aug 11 '15 at 9:47














0












0








0







Sorry, pretty awful title to describe my question.



Sometimes I like playing around with series expansions for certain functions on Mathematica, and if the function has a singularity at a point $b$, sometimes the little suggestion box will say something like "Series around $ x=b$" and will give me a series expansion around that point. I know this number is special, I don't know why, but sometimes at that series expansion it will have the obvious singularity, like $dfrac{1}{x-b}$ and then after that a finite number followed by more powers of $x$ with coefficients.



What is that finite number called?










share|cite|improve this question















Sorry, pretty awful title to describe my question.



Sometimes I like playing around with series expansions for certain functions on Mathematica, and if the function has a singularity at a point $b$, sometimes the little suggestion box will say something like "Series around $ x=b$" and will give me a series expansion around that point. I know this number is special, I don't know why, but sometimes at that series expansion it will have the obvious singularity, like $dfrac{1}{x-b}$ and then after that a finite number followed by more powers of $x$ with coefficients.



What is that finite number called?







calculus sequences-and-series terminology






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Aug 11 '15 at 9:50









joriki

170k10183343




170k10183343










asked Aug 11 '15 at 9:40









Dave huffDave huff

478211




478211












  • What number?${}$
    – Git Gud
    Aug 11 '15 at 9:41










  • The coefficient of $(x-b)^0$? Is it the residue?
    – Empy2
    Aug 11 '15 at 9:45










  • I have an example: wolframalpha.com/input/?i=1%2F%28s*%28s%2B1%29%29 If you go to where it says Series expansion at s=0, it will give 1/s-1+s+.....i'm talking about the -1 in that series expansion. Its not always -1, and sometimes there is no constant term at a series expansion around a singularity, but is there a name for the constant term in a series expansion for a function around its singularity?
    – Dave huff
    Aug 11 '15 at 9:45










  • Don't you mean $(x-b)^{-1}$ ?
    – Yves Daoust
    Aug 11 '15 at 9:46










  • My bad on the description, its not a coefficient on any of the series terms, its a constant number, there is no x multiplying it.
    – Dave huff
    Aug 11 '15 at 9:47


















  • What number?${}$
    – Git Gud
    Aug 11 '15 at 9:41










  • The coefficient of $(x-b)^0$? Is it the residue?
    – Empy2
    Aug 11 '15 at 9:45










  • I have an example: wolframalpha.com/input/?i=1%2F%28s*%28s%2B1%29%29 If you go to where it says Series expansion at s=0, it will give 1/s-1+s+.....i'm talking about the -1 in that series expansion. Its not always -1, and sometimes there is no constant term at a series expansion around a singularity, but is there a name for the constant term in a series expansion for a function around its singularity?
    – Dave huff
    Aug 11 '15 at 9:45










  • Don't you mean $(x-b)^{-1}$ ?
    – Yves Daoust
    Aug 11 '15 at 9:46










  • My bad on the description, its not a coefficient on any of the series terms, its a constant number, there is no x multiplying it.
    – Dave huff
    Aug 11 '15 at 9:47
















What number?${}$
– Git Gud
Aug 11 '15 at 9:41




What number?${}$
– Git Gud
Aug 11 '15 at 9:41












The coefficient of $(x-b)^0$? Is it the residue?
– Empy2
Aug 11 '15 at 9:45




The coefficient of $(x-b)^0$? Is it the residue?
– Empy2
Aug 11 '15 at 9:45












I have an example: wolframalpha.com/input/?i=1%2F%28s*%28s%2B1%29%29 If you go to where it says Series expansion at s=0, it will give 1/s-1+s+.....i'm talking about the -1 in that series expansion. Its not always -1, and sometimes there is no constant term at a series expansion around a singularity, but is there a name for the constant term in a series expansion for a function around its singularity?
– Dave huff
Aug 11 '15 at 9:45




I have an example: wolframalpha.com/input/?i=1%2F%28s*%28s%2B1%29%29 If you go to where it says Series expansion at s=0, it will give 1/s-1+s+.....i'm talking about the -1 in that series expansion. Its not always -1, and sometimes there is no constant term at a series expansion around a singularity, but is there a name for the constant term in a series expansion for a function around its singularity?
– Dave huff
Aug 11 '15 at 9:45












Don't you mean $(x-b)^{-1}$ ?
– Yves Daoust
Aug 11 '15 at 9:46




Don't you mean $(x-b)^{-1}$ ?
– Yves Daoust
Aug 11 '15 at 9:46












My bad on the description, its not a coefficient on any of the series terms, its a constant number, there is no x multiplying it.
– Dave huff
Aug 11 '15 at 9:47




My bad on the description, its not a coefficient on any of the series terms, its a constant number, there is no x multiplying it.
– Dave huff
Aug 11 '15 at 9:47










1 Answer
1






active

oldest

votes


















2














This is usually called the constant term. See e.g. mathwords.






share|cite|improve this answer





















    Your Answer





    StackExchange.ifUsing("editor", function () {
    return StackExchange.using("mathjaxEditing", function () {
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    });
    });
    }, "mathjax-editing");

    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "69"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














    draft saved

    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f1392963%2fwhat-is-this-number-called%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    2














    This is usually called the constant term. See e.g. mathwords.






    share|cite|improve this answer


























      2














      This is usually called the constant term. See e.g. mathwords.






      share|cite|improve this answer
























        2












        2








        2






        This is usually called the constant term. See e.g. mathwords.






        share|cite|improve this answer












        This is usually called the constant term. See e.g. mathwords.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Aug 11 '15 at 9:50









        jorikijoriki

        170k10183343




        170k10183343






























            draft saved

            draft discarded




















































            Thanks for contributing an answer to Mathematics Stack Exchange!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid



            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.


            Use MathJax to format equations. MathJax reference.


            To learn more, see our tips on writing great answers.





            Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


            Please pay close attention to the following guidance:


            • Please be sure to answer the question. Provide details and share your research!

            But avoid



            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f1392963%2fwhat-is-this-number-called%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            Quarter-circle Tiles

            build a pushdown automaton that recognizes the reverse language of a given pushdown automaton?

            Mont Emei