Calculate the integral of exp(z)/sin(z) over |z|=4 using the residue theorem.












2














Click to view the integral in correct format.



Calculate the integral of exp(z)/sin(z) (as in the image above) over the positively oriented circle defined by |z|=4 using the residue theorem.



This is a question that I'm just not sure I'm doing completely correct and would like some confirmation or correction. Pictures of my work are added below.



From exp(z)/sin(z), the singularities within |z|=4 are 0, pi, and -pi where pi is in reference to the 3.14... pi. I used the residue theorem with the p(z) and q(z) standards where Res (f, z0) = p(z0)/q'(zo) to get



Res (f, 0) = exp(z)/cos(z) | (z=0) = 1



Res (f, pi) = exp(z)/cos(z) | (z=pi) = -e^(pi)



Res (f, -pi) = exp(z)/cos(z) | (z=-pi) = -e^(-pi)



Thus, the residue theorem yields the (unsimplified) answer of 2(pi)(i)(1-e^(pi)-e^(-pi)).



Click to view the guidelines I assumed to start my calculation.



Click to view my calculations and answer in a more legible format.










share|cite|improve this question
























  • Hi and welcome to the site! Since this is a site that encourages and helps with learning, it is best if you show your own ideas and efforts in solving the question. Can you edit your question to add your thoughts and ideas about it? Don't worry if it's wrong - that's what we're here for.
    – 5xum
    Nov 27 at 10:49










  • Also, don't get discouraged by the downvote. I downvoted the question and voted to close it because at the moment, it is not up to site standards (you have shown no work you did on your own). If you edit your question so that you show what you tried and how far you got, I will not only remove the downvote, I will add an upvote.
    – 5xum
    Nov 27 at 10:49






  • 1




    Thank you for getting me up to speed with the site standards! I've added my calculations as well as links to my work in a more readable fashion. Hope this satisfies the guidelines and helps to see where I might be going wrong in my work!
    – Josie Evans
    Nov 27 at 11:35










  • As promised, I retracted my close vote :)
    – 5xum
    Nov 27 at 11:40
















2














Click to view the integral in correct format.



Calculate the integral of exp(z)/sin(z) (as in the image above) over the positively oriented circle defined by |z|=4 using the residue theorem.



This is a question that I'm just not sure I'm doing completely correct and would like some confirmation or correction. Pictures of my work are added below.



From exp(z)/sin(z), the singularities within |z|=4 are 0, pi, and -pi where pi is in reference to the 3.14... pi. I used the residue theorem with the p(z) and q(z) standards where Res (f, z0) = p(z0)/q'(zo) to get



Res (f, 0) = exp(z)/cos(z) | (z=0) = 1



Res (f, pi) = exp(z)/cos(z) | (z=pi) = -e^(pi)



Res (f, -pi) = exp(z)/cos(z) | (z=-pi) = -e^(-pi)



Thus, the residue theorem yields the (unsimplified) answer of 2(pi)(i)(1-e^(pi)-e^(-pi)).



Click to view the guidelines I assumed to start my calculation.



Click to view my calculations and answer in a more legible format.










share|cite|improve this question
























  • Hi and welcome to the site! Since this is a site that encourages and helps with learning, it is best if you show your own ideas and efforts in solving the question. Can you edit your question to add your thoughts and ideas about it? Don't worry if it's wrong - that's what we're here for.
    – 5xum
    Nov 27 at 10:49










  • Also, don't get discouraged by the downvote. I downvoted the question and voted to close it because at the moment, it is not up to site standards (you have shown no work you did on your own). If you edit your question so that you show what you tried and how far you got, I will not only remove the downvote, I will add an upvote.
    – 5xum
    Nov 27 at 10:49






  • 1




    Thank you for getting me up to speed with the site standards! I've added my calculations as well as links to my work in a more readable fashion. Hope this satisfies the guidelines and helps to see where I might be going wrong in my work!
    – Josie Evans
    Nov 27 at 11:35










  • As promised, I retracted my close vote :)
    – 5xum
    Nov 27 at 11:40














2












2








2


0





Click to view the integral in correct format.



Calculate the integral of exp(z)/sin(z) (as in the image above) over the positively oriented circle defined by |z|=4 using the residue theorem.



This is a question that I'm just not sure I'm doing completely correct and would like some confirmation or correction. Pictures of my work are added below.



From exp(z)/sin(z), the singularities within |z|=4 are 0, pi, and -pi where pi is in reference to the 3.14... pi. I used the residue theorem with the p(z) and q(z) standards where Res (f, z0) = p(z0)/q'(zo) to get



Res (f, 0) = exp(z)/cos(z) | (z=0) = 1



Res (f, pi) = exp(z)/cos(z) | (z=pi) = -e^(pi)



Res (f, -pi) = exp(z)/cos(z) | (z=-pi) = -e^(-pi)



Thus, the residue theorem yields the (unsimplified) answer of 2(pi)(i)(1-e^(pi)-e^(-pi)).



Click to view the guidelines I assumed to start my calculation.



Click to view my calculations and answer in a more legible format.










share|cite|improve this question















Click to view the integral in correct format.



Calculate the integral of exp(z)/sin(z) (as in the image above) over the positively oriented circle defined by |z|=4 using the residue theorem.



This is a question that I'm just not sure I'm doing completely correct and would like some confirmation or correction. Pictures of my work are added below.



From exp(z)/sin(z), the singularities within |z|=4 are 0, pi, and -pi where pi is in reference to the 3.14... pi. I used the residue theorem with the p(z) and q(z) standards where Res (f, z0) = p(z0)/q'(zo) to get



Res (f, 0) = exp(z)/cos(z) | (z=0) = 1



Res (f, pi) = exp(z)/cos(z) | (z=pi) = -e^(pi)



Res (f, -pi) = exp(z)/cos(z) | (z=-pi) = -e^(-pi)



Thus, the residue theorem yields the (unsimplified) answer of 2(pi)(i)(1-e^(pi)-e^(-pi)).



Click to view the guidelines I assumed to start my calculation.



Click to view my calculations and answer in a more legible format.







complex-analysis exponential-function mathematical-physics trigonometric-integrals several-complex-variables






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 27 at 11:31

























asked Nov 27 at 10:48









Josie Evans

162




162












  • Hi and welcome to the site! Since this is a site that encourages and helps with learning, it is best if you show your own ideas and efforts in solving the question. Can you edit your question to add your thoughts and ideas about it? Don't worry if it's wrong - that's what we're here for.
    – 5xum
    Nov 27 at 10:49










  • Also, don't get discouraged by the downvote. I downvoted the question and voted to close it because at the moment, it is not up to site standards (you have shown no work you did on your own). If you edit your question so that you show what you tried and how far you got, I will not only remove the downvote, I will add an upvote.
    – 5xum
    Nov 27 at 10:49






  • 1




    Thank you for getting me up to speed with the site standards! I've added my calculations as well as links to my work in a more readable fashion. Hope this satisfies the guidelines and helps to see where I might be going wrong in my work!
    – Josie Evans
    Nov 27 at 11:35










  • As promised, I retracted my close vote :)
    – 5xum
    Nov 27 at 11:40


















  • Hi and welcome to the site! Since this is a site that encourages and helps with learning, it is best if you show your own ideas and efforts in solving the question. Can you edit your question to add your thoughts and ideas about it? Don't worry if it's wrong - that's what we're here for.
    – 5xum
    Nov 27 at 10:49










  • Also, don't get discouraged by the downvote. I downvoted the question and voted to close it because at the moment, it is not up to site standards (you have shown no work you did on your own). If you edit your question so that you show what you tried and how far you got, I will not only remove the downvote, I will add an upvote.
    – 5xum
    Nov 27 at 10:49






  • 1




    Thank you for getting me up to speed with the site standards! I've added my calculations as well as links to my work in a more readable fashion. Hope this satisfies the guidelines and helps to see where I might be going wrong in my work!
    – Josie Evans
    Nov 27 at 11:35










  • As promised, I retracted my close vote :)
    – 5xum
    Nov 27 at 11:40
















Hi and welcome to the site! Since this is a site that encourages and helps with learning, it is best if you show your own ideas and efforts in solving the question. Can you edit your question to add your thoughts and ideas about it? Don't worry if it's wrong - that's what we're here for.
– 5xum
Nov 27 at 10:49




Hi and welcome to the site! Since this is a site that encourages and helps with learning, it is best if you show your own ideas and efforts in solving the question. Can you edit your question to add your thoughts and ideas about it? Don't worry if it's wrong - that's what we're here for.
– 5xum
Nov 27 at 10:49












Also, don't get discouraged by the downvote. I downvoted the question and voted to close it because at the moment, it is not up to site standards (you have shown no work you did on your own). If you edit your question so that you show what you tried and how far you got, I will not only remove the downvote, I will add an upvote.
– 5xum
Nov 27 at 10:49




Also, don't get discouraged by the downvote. I downvoted the question and voted to close it because at the moment, it is not up to site standards (you have shown no work you did on your own). If you edit your question so that you show what you tried and how far you got, I will not only remove the downvote, I will add an upvote.
– 5xum
Nov 27 at 10:49




1




1




Thank you for getting me up to speed with the site standards! I've added my calculations as well as links to my work in a more readable fashion. Hope this satisfies the guidelines and helps to see where I might be going wrong in my work!
– Josie Evans
Nov 27 at 11:35




Thank you for getting me up to speed with the site standards! I've added my calculations as well as links to my work in a more readable fashion. Hope this satisfies the guidelines and helps to see where I might be going wrong in my work!
– Josie Evans
Nov 27 at 11:35












As promised, I retracted my close vote :)
– 5xum
Nov 27 at 11:40




As promised, I retracted my close vote :)
– 5xum
Nov 27 at 11:40










1 Answer
1






active

oldest

votes


















1














Your computations of the residues are correct. And the computation of the integral (via residue theorem) also looks fine.






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%2f3015638%2fcalculate-the-integral-of-expz-sinz-over-z-4-using-the-residue-theorem%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









    1














    Your computations of the residues are correct. And the computation of the integral (via residue theorem) also looks fine.






    share|cite|improve this answer


























      1














      Your computations of the residues are correct. And the computation of the integral (via residue theorem) also looks fine.






      share|cite|improve this answer
























        1












        1








        1






        Your computations of the residues are correct. And the computation of the integral (via residue theorem) also looks fine.






        share|cite|improve this answer












        Your computations of the residues are correct. And the computation of the integral (via residue theorem) also looks fine.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 27 at 12:02









        Fred

        44.2k1845




        44.2k1845






























            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%2f3015638%2fcalculate-the-integral-of-expz-sinz-over-z-4-using-the-residue-theorem%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

            Bundesstraße 106

            Verónica Boquete

            Ida-Boy-Ed-Garten