Integrating function with /; in its definitionHow to make InverseFunction work on function defined with...

The need of reserving one's ability in job interviews

Do natural melee weapons (from racial traits) trigger Improved Divine Smite?

Was it really inappropriate to write a pull request for the company I interviewed with?

Can inspiration allow the Rogue to make a Sneak Attack?

Preparing as much as possible of a cake in advance

Can you run a ground wire from stove directly to ground pole in the ground

Problems with rounding giving too many digits

Dukha vs legitimate need

When to use the term transposed instead of modulation?

What can I do if someone tampers with my SSH public key?

Is there a way to find out the age of climbing ropes?

Can a Mimic (container form) actually hold loot?

Error in TransformedField

Should I use HTTPS on a domain that will only be used for redirection?

Naming Characters after Friends/Family

Can a Mexican citizen living in US under DACA drive to Canada?

Called into a meeting and told we are being made redundant (laid off) and "not to share outside". Can I tell my partner?

ESPP--any reason not to go all in?

Does the US political system, in principle, allow for a no-party system?

Can a space-faring robot still function over a billion years?

I can't die. Who am I?

Is "cogitate" an appropriate word for this?

Why aren't there more gauls like Obelix?

Should we avoid writing fiction about historical events without extensive research?



Integrating function with /; in its definition


How to make InverseFunction work on function defined with restriction on argumentsIntegrating a periodic functionHow to Integrate trivial products of DiracDeltaIntegrating expressions with several terms and delta functionsSubstitute a function's definition for its nameMathematica `Integrate` evaluates some integrals only with some specific scaling factorPlotting a function involving Nsolve in its definitionDefinition of a periodic function doesn't work when given as the forcing function of an ODEProblem with pendulum code cant get to plot Mathematica 11.3Define Function using another Function and plot













3












$begingroup$


why



f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


return unevaluated? Notice that the above definition of f[x] works OK with other Mathematica functions, such as Plot



Plot[f[x], {x, 0, 2 Pi}]


Mathematica graphics



While the following works with Integrate



f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


I am using version 11.3 on windows.










share|improve this question











$endgroup$








  • 3




    $begingroup$
    It's better to use ConditionalExpression, e.g., Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
    $endgroup$
    – Carl Woll
    3 hours ago
















3












$begingroup$


why



f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


return unevaluated? Notice that the above definition of f[x] works OK with other Mathematica functions, such as Plot



Plot[f[x], {x, 0, 2 Pi}]


Mathematica graphics



While the following works with Integrate



f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


I am using version 11.3 on windows.










share|improve this question











$endgroup$








  • 3




    $begingroup$
    It's better to use ConditionalExpression, e.g., Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
    $endgroup$
    – Carl Woll
    3 hours ago














3












3








3





$begingroup$


why



f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


return unevaluated? Notice that the above definition of f[x] works OK with other Mathematica functions, such as Plot



Plot[f[x], {x, 0, 2 Pi}]


Mathematica graphics



While the following works with Integrate



f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


I am using version 11.3 on windows.










share|improve this question











$endgroup$




why



f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


return unevaluated? Notice that the above definition of f[x] works OK with other Mathematica functions, such as Plot



Plot[f[x], {x, 0, 2 Pi}]


Mathematica graphics



While the following works with Integrate



f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]


I am using version 11.3 on windows.







calculus-and-analysis function-construction






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 13 mins ago









J. M. is computer-less

97.3k10303463




97.3k10303463










asked 3 hours ago









NasserNasser

58.1k489206




58.1k489206








  • 3




    $begingroup$
    It's better to use ConditionalExpression, e.g., Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
    $endgroup$
    – Carl Woll
    3 hours ago














  • 3




    $begingroup$
    It's better to use ConditionalExpression, e.g., Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
    $endgroup$
    – Carl Woll
    3 hours ago








3




3




$begingroup$
It's better to use ConditionalExpression, e.g., Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago




$begingroup$
It's better to use ConditionalExpression, e.g., Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago










1 Answer
1






active

oldest

votes


















5












$begingroup$

f[x_ /; x>=0]:=x means "if whatever>=0 rewrite f[whatever] as whatever. But that doesn't apply to f[x] when x is a symbol without a numerical value. Thus, f[x] simply remains f[x]. For abstracting the notion of a function with a break like this, use Piecewise or HeavisideTheta: Integrate understands what those mean.






share|improve this answer









$endgroup$













    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: "387"
    };
    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: false,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: null,
    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
    },
    onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














    draft saved

    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f192838%2fintegrating-function-with-in-its-definition%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









    5












    $begingroup$

    f[x_ /; x>=0]:=x means "if whatever>=0 rewrite f[whatever] as whatever. But that doesn't apply to f[x] when x is a symbol without a numerical value. Thus, f[x] simply remains f[x]. For abstracting the notion of a function with a break like this, use Piecewise or HeavisideTheta: Integrate understands what those mean.






    share|improve this answer









    $endgroup$


















      5












      $begingroup$

      f[x_ /; x>=0]:=x means "if whatever>=0 rewrite f[whatever] as whatever. But that doesn't apply to f[x] when x is a symbol without a numerical value. Thus, f[x] simply remains f[x]. For abstracting the notion of a function with a break like this, use Piecewise or HeavisideTheta: Integrate understands what those mean.






      share|improve this answer









      $endgroup$
















        5












        5








        5





        $begingroup$

        f[x_ /; x>=0]:=x means "if whatever>=0 rewrite f[whatever] as whatever. But that doesn't apply to f[x] when x is a symbol without a numerical value. Thus, f[x] simply remains f[x]. For abstracting the notion of a function with a break like this, use Piecewise or HeavisideTheta: Integrate understands what those mean.






        share|improve this answer









        $endgroup$



        f[x_ /; x>=0]:=x means "if whatever>=0 rewrite f[whatever] as whatever. But that doesn't apply to f[x] when x is a symbol without a numerical value. Thus, f[x] simply remains f[x]. For abstracting the notion of a function with a break like this, use Piecewise or HeavisideTheta: Integrate understands what those mean.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 3 hours ago









        John DotyJohn Doty

        7,32811124




        7,32811124






























            draft saved

            draft discarded




















































            Thanks for contributing an answer to Mathematica 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.




            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f192838%2fintegrating-function-with-in-its-definition%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

            Щит и меч (фильм) Содержание Названия серий | Сюжет |...

            is 'sed' thread safeWhat should someone know about using Python scripts in the shell?Nexenta bash script uses...

            Meter-Bus Содержание Параметры шины | Стандартизация |...