Complex Analysis: An Integral from

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  • Опубліковано 6 лис 2024

КОМЕНТАРІ • 25

  • @Decrupt
    @Decrupt 2 роки тому +14

    Double the contour integrals, double the amazing content!

  • @user-wu8yq1rb9t
    @user-wu8yq1rb9t 2 роки тому +8

    Min: 22:42
    I think you need *Hagoromo Chalk* , because the *Hagoromo Chalk* are antigravity!!
    Min 25:00 .... 27:00 thanks for details.
    Just Great (one of the best of yours) 🤓
    Thank you so much dear *QN³* ❤️

  • @The1RandomFool
    @The1RandomFool 2 роки тому +3

    Very nice, this is the exact method I used when he posted that video.

  • @Alex_Deam
    @Alex_Deam 2 роки тому +2

    31:56 Real analysis could never

  • @user-wu8yq1rb9t
    @user-wu8yq1rb9t 2 роки тому +3

    Hello dear *QN³* ...
    One integral with two methods?!
    Complex one with You ( dear *QN³* ) and the other with Penn?!
    *Super Duper Cool*

  • @kummer45
    @kummer45 2 роки тому +2

    Contour integral is the real deal. I always hate when people on some books come up with the paths without explaining how they where constructed. The contour path should be selected localizing the poles in the situation. This should be explained further. The rest is easy to follow and the classical exercises of the theorem.
    The deal here is how the practitioner comes up with the adequate contour and the identification of the relevant poles.

    • @djangogeek
      @djangogeek Рік тому

      I will be posting a solution addressing exactly this concern. Getting the right contour should be a straightforward mechanical process, not an art form.

    • @djangogeek
      @djangogeek Рік тому

      video posted on my channel.

  • @rahulnadig9873
    @rahulnadig9873 2 роки тому +3

    Keep pumping it out maths god

  • @jkid1134
    @jkid1134 Рік тому +1

    Yo wtf this is sick

  • @holyshit922
    @holyshit922 Рік тому

    Firsty I substituted y^2=x to get rid of square root then I split interval into [0,1] and [1,infinity]
    Int(8ln^2(y)/(1-y^2)^2,u=0..1)+Int(8ln^2(y)/(1-y^2)^2,u=1..infinity)
    then substituted y = 1/u in the integral Int(8ln^2(y)/(1-y^2)^2,u=1..infinity)
    to get 8Int((1+u^2)ln^2(u)/(1-u^2)^2,u=0..1)
    Then I integrated indefinite integral by parts 8Int((1+u^2)ln^2(u)/(1-u^2)^2,u) (differentiating log)
    and then calculate the limits
    Finally I got -16Int(ln(u)/(1-u^2),u=0..1)
    From here I expanded 1/(1-u^2) as geometric series
    and calculated integral Int(u^(2n)ln(u),u=0..1) by parts
    and got
    16sum(1/(2n+1)^2,n=0..infinity)
    16(sum(1/n^2,n=1..infinity) - sum(1/(2n)^2,n=1..infinity))
    16(sum(1/n^2,n=1..infinity) - 1/4sum(1/n^2,n=1..infinity))
    16*3/4sum(1/n^2,n=1..infinity)
    12sum(1/n^2,n=1..infinity)
    2π^2

  • @ameliaC-xg8rg
    @ameliaC-xg8rg 2 роки тому +2

    Great content as always :P I hope you two could make a collab video sometime, I'm sure it would be awesome

  • @rishetmehra4364
    @rishetmehra4364 6 місяців тому

    what are branch points and branch cuts?

  • @benjaminjohnson-martin1248
    @benjaminjohnson-martin1248 2 роки тому

    The cursed bicycle.

  • @user-wu8yq1rb9t
    @user-wu8yq1rb9t 2 роки тому +1

    Hello dear *QN³*
    Probably you watched the last video of Dr. Penn (looks crazy) already ....
    You think its answer is right?!
    Honestly, I have some problem with it. I'm not sure, but I think we have some problem on it (at least in details)!
    I hope you'll have a plan for it.
    Dear *QN³* ❤️

  • @soup1649
    @soup1649 2 роки тому

    hello can you do a video on the integral from 0 to infinity of cosx/(x^3+x^2+x+1) dx please!
    i've tried to evaluate it by contour integration but i'm stuck

  • @Leomenxd
    @Leomenxd 2 роки тому

    All this mess just to make two pies square shaped, damn.

  • @burpleson
    @burpleson 2 роки тому

    Four integrals for the price of one.

  • @stephyjose9533
    @stephyjose9533 Рік тому

    Can you help compute the integral $\int_ {- \infty} ^ {\infty} dk\frac {e^ {-a\sqrt {s+\iota k}} e^ {-a\sqrt {s-\iota k}}} {(s+\iota k) (s-\iota k)} $ using complex analysis?

  • @GreenMeansGOF
    @GreenMeansGOF Рік тому

    Is it possible do solve integral of sin^2(x)/(1+x^2) from 1 to infinity? Wolframalpha only gives a decimal answer so I assume the answer is no.

    • @vascomanteigas9433
      @vascomanteigas9433 Рік тому

      The Analytical Answer needs to use the incomplete gamma function.

    • @GreenMeansGOF
      @GreenMeansGOF Рік тому

      @@vascomanteigas9433 what is the final answer?

  • @nasim09021975
    @nasim09021975 Рік тому

    How about solving

    ∫ [ exp(-x) * ln (x) * ln (x) ] dx
    0

  • @nurhaudi112
    @nurhaudi112 7 місяців тому

    Mirip sudirman wkwk

  • @KStarGamer_
    @KStarGamer_ 2 роки тому +1

    There are some alternative methods on MSE for anyone interested: questions/4427604/evaluate-int-0-infty-frac-lnx2-sqrtx1-x2dx (I had to split up the URL because UA-cam would delete my comment otherwise. Sorry about that)