Is this a typo in Section 1.8.1 Mathematics for Computer Science?How can I learn about proofs for computer science?How can I start to learn proof theory?Proving the existence of a proof without actually giving a proofProof by well ordering: Every positive integer greater than one can be factored as a product of primes.Gentzen and computer scienceElegant demonstration with minimum category theory knowledgeDifferent definitions of Natural Numbers and Proof by ContradictionProve $3^2n-5$ is a multiple of $4$Defining new symbols in a proof, when is this justified?Prove convergence rate to zero increases as n increases

How do I calculate how many of an item I'll have in this inventory system?

How to pass hash as password to ssh server

It is as simple as ABC

How do LIGO and VIRGO know that a gravitational wave has its origin in a neutron star or a black hole?

Should I simplify my writing in a foreign country?

Why do these characters still seem to be the same age after the events of Endgame?

Nested loops to process groups of pictures

Should I mention being denied entry to UK due to a confusion in my Visa and Ticket bookings?

Find magical solution to magical equation

Where are the "shires" in the UK?

Install LibreOffice-Writer Only not LibreOffice whole package

Dihedral group D4 composition with custom labels

Constitutional limitation of criminalizing behavior in US law?

Does XQuartz work on macOS Mojave?

History of the kernel of a homomorphism?

Why doesn't ever smooth vector bundle admits a line bundle?

Hostile Divisor Numbers

Can I use a Cat5e cable with an RJ45 and Cat6 port?

Is an HNN extension of a virtually torsion-free group virtually torsion-free?

Why would a military not separate its forces into different branches?

Is the book wrong about the Nyquist Sampling Criterion?

Is there an age requirement to play in Adventurers League?

Why does sound not move through a wall?

SOQL query WHERE filter by specific months



Is this a typo in Section 1.8.1 Mathematics for Computer Science?


How can I learn about proofs for computer science?How can I start to learn proof theory?Proving the existence of a proof without actually giving a proofProof by well ordering: Every positive integer greater than one can be factored as a product of primes.Gentzen and computer scienceElegant demonstration with minimum category theory knowledgeDifferent definitions of Natural Numbers and Proof by ContradictionProve $3^2n-5$ is a multiple of $4$Defining new symbols in a proof, when is this justified?Prove convergence rate to zero increases as n increases













2












$begingroup$


enter image description here



Am I completely mistake or is it suppose to say $n^2$ is a multiple of 2 and therefore $n$ must be a multiple of 4?



This is from MIT's Mathematics for Computer Science










share|cite|improve this question









$endgroup$











  • $begingroup$
    Generally: If $m,n$ are positive integers and $m^1/n$ is not an integer then $m^1/n$ is irrational. Proved by a similar method.
    $endgroup$
    – DanielWainfleet
    Apr 26 at 1:48






  • 1




    $begingroup$
    What makes you think this is a mistake?
    $endgroup$
    – Servaes
    Apr 26 at 7:31















2












$begingroup$


enter image description here



Am I completely mistake or is it suppose to say $n^2$ is a multiple of 2 and therefore $n$ must be a multiple of 4?



This is from MIT's Mathematics for Computer Science










share|cite|improve this question









$endgroup$











  • $begingroup$
    Generally: If $m,n$ are positive integers and $m^1/n$ is not an integer then $m^1/n$ is irrational. Proved by a similar method.
    $endgroup$
    – DanielWainfleet
    Apr 26 at 1:48






  • 1




    $begingroup$
    What makes you think this is a mistake?
    $endgroup$
    – Servaes
    Apr 26 at 7:31













2












2








2


1



$begingroup$


enter image description here



Am I completely mistake or is it suppose to say $n^2$ is a multiple of 2 and therefore $n$ must be a multiple of 4?



This is from MIT's Mathematics for Computer Science










share|cite|improve this question









$endgroup$




enter image description here



Am I completely mistake or is it suppose to say $n^2$ is a multiple of 2 and therefore $n$ must be a multiple of 4?



This is from MIT's Mathematics for Computer Science







proof-explanation proof-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Apr 26 at 1:14









doctopusdoctopus

1414




1414











  • $begingroup$
    Generally: If $m,n$ are positive integers and $m^1/n$ is not an integer then $m^1/n$ is irrational. Proved by a similar method.
    $endgroup$
    – DanielWainfleet
    Apr 26 at 1:48






  • 1




    $begingroup$
    What makes you think this is a mistake?
    $endgroup$
    – Servaes
    Apr 26 at 7:31
















  • $begingroup$
    Generally: If $m,n$ are positive integers and $m^1/n$ is not an integer then $m^1/n$ is irrational. Proved by a similar method.
    $endgroup$
    – DanielWainfleet
    Apr 26 at 1:48






  • 1




    $begingroup$
    What makes you think this is a mistake?
    $endgroup$
    – Servaes
    Apr 26 at 7:31















$begingroup$
Generally: If $m,n$ are positive integers and $m^1/n$ is not an integer then $m^1/n$ is irrational. Proved by a similar method.
$endgroup$
– DanielWainfleet
Apr 26 at 1:48




$begingroup$
Generally: If $m,n$ are positive integers and $m^1/n$ is not an integer then $m^1/n$ is irrational. Proved by a similar method.
$endgroup$
– DanielWainfleet
Apr 26 at 1:48




1




1




$begingroup$
What makes you think this is a mistake?
$endgroup$
– Servaes
Apr 26 at 7:31




$begingroup$
What makes you think this is a mistake?
$endgroup$
– Servaes
Apr 26 at 7:31










2 Answers
2






active

oldest

votes


















3












$begingroup$

No, it is correct. The point is that $2d^2=n^2$ implies $n^2$ is even, and only even numbers square to give an even number, so $n$ much be even, so $n^2$ is then actually a multiple of $4$.






share|cite|improve this answer









$endgroup$












  • $begingroup$
    This makes sense thanks
    $endgroup$
    – doctopus
    2 days ago


















3












$begingroup$

No. $6^2$ is a multiple of $2$ but $6$ is not a multiple of $4$. If $n=2k$ then for sure $n^2=4k^2$. So, MIT is right.






share|cite|improve this answer









$endgroup$













    Your Answer








    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%2f3202666%2fis-this-a-typo-in-section-1-8-1-mathematics-for-computer-science%23new-answer', 'question_page');

    );

    Post as a guest















    Required, but never shown

























    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    3












    $begingroup$

    No, it is correct. The point is that $2d^2=n^2$ implies $n^2$ is even, and only even numbers square to give an even number, so $n$ much be even, so $n^2$ is then actually a multiple of $4$.






    share|cite|improve this answer









    $endgroup$












    • $begingroup$
      This makes sense thanks
      $endgroup$
      – doctopus
      2 days ago















    3












    $begingroup$

    No, it is correct. The point is that $2d^2=n^2$ implies $n^2$ is even, and only even numbers square to give an even number, so $n$ much be even, so $n^2$ is then actually a multiple of $4$.






    share|cite|improve this answer









    $endgroup$












    • $begingroup$
      This makes sense thanks
      $endgroup$
      – doctopus
      2 days ago













    3












    3








    3





    $begingroup$

    No, it is correct. The point is that $2d^2=n^2$ implies $n^2$ is even, and only even numbers square to give an even number, so $n$ much be even, so $n^2$ is then actually a multiple of $4$.






    share|cite|improve this answer









    $endgroup$



    No, it is correct. The point is that $2d^2=n^2$ implies $n^2$ is even, and only even numbers square to give an even number, so $n$ much be even, so $n^2$ is then actually a multiple of $4$.







    share|cite|improve this answer












    share|cite|improve this answer



    share|cite|improve this answer










    answered Apr 26 at 1:21









    John DoeJohn Doe

    12.6k11441




    12.6k11441











    • $begingroup$
      This makes sense thanks
      $endgroup$
      – doctopus
      2 days ago
















    • $begingroup$
      This makes sense thanks
      $endgroup$
      – doctopus
      2 days ago















    $begingroup$
    This makes sense thanks
    $endgroup$
    – doctopus
    2 days ago




    $begingroup$
    This makes sense thanks
    $endgroup$
    – doctopus
    2 days ago











    3












    $begingroup$

    No. $6^2$ is a multiple of $2$ but $6$ is not a multiple of $4$. If $n=2k$ then for sure $n^2=4k^2$. So, MIT is right.






    share|cite|improve this answer









    $endgroup$

















      3












      $begingroup$

      No. $6^2$ is a multiple of $2$ but $6$ is not a multiple of $4$. If $n=2k$ then for sure $n^2=4k^2$. So, MIT is right.






      share|cite|improve this answer









      $endgroup$















        3












        3








        3





        $begingroup$

        No. $6^2$ is a multiple of $2$ but $6$ is not a multiple of $4$. If $n=2k$ then for sure $n^2=4k^2$. So, MIT is right.






        share|cite|improve this answer









        $endgroup$



        No. $6^2$ is a multiple of $2$ but $6$ is not a multiple of $4$. If $n=2k$ then for sure $n^2=4k^2$. So, MIT is right.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Apr 26 at 1:19









        RandallRandall

        10.9k11431




        10.9k11431



























            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.




            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3202666%2fis-this-a-typo-in-section-1-8-1-mathematics-for-computer-science%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

            Wikipedia:Vital articles Мазмуну Biography - Өмүр баян Philosophy and psychology - Философия жана психология Religion - Дин Social sciences - Коомдук илимдер Language and literature - Тил жана адабият Science - Илим Technology - Технология Arts and recreation - Искусство жана эс алуу History and geography - Тарых жана география Навигация менюсу

            Bruxelas-Capital Índice Historia | Composición | Situación lingüística | Clima | Cidades irmandadas | Notas | Véxase tamén | Menú de navegacióneO uso das linguas en Bruxelas e a situación do neerlandés"Rexión de Bruxelas Capital"o orixinalSitio da rexiónPáxina de Bruselas no sitio da Oficina de Promoción Turística de Valonia e BruxelasMapa Interactivo da Rexión de Bruxelas-CapitaleeWorldCat332144929079854441105155190212ID28008674080552-90000 0001 0666 3698n94104302ID540940339365017018237

            What should I write in an apology letter, since I have decided not to join a company after accepting an offer letterShould I keep looking after accepting a job offer?What should I do when I've been verbally told I would get an offer letter, but still haven't gotten one after 4 weeks?Do I accept an offer from a company that I am not likely to join?New job hasn't confirmed starting date and I want to give current employer as much notice as possibleHow should I address my manager in my resignation letter?HR delayed background verification, now jobless as resignedNo email communication after accepting a formal written offer. How should I phrase the call?What should I do if after receiving a verbal offer letter I am informed that my written job offer is put on hold due to some internal issues?Should I inform the current employer that I am about to resign within 1-2 weeks since I have signed the offer letter and waiting for visa?What company will do, if I send their offer letter to another company