A deceivingly difficult integral

When Forest Grump said "life is like a box of chocolates, you never know what you're going to get", I'm sure he wasn't talking about integral calculus. However this integral fits the bill quite well.
Proof for ln(cos(x)) series:
• My take on this on won...
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Пікірлер: 42

  • @Tosi31415
    @Tosi31415Ай бұрын

    the result happens to be extremely close to the euler mascheroni constant aswell

  • @ericthegreat7805

    @ericthegreat7805

    28 күн бұрын

    Oily-Macaroni

  • @xloppyschannel4881
    @xloppyschannel488129 күн бұрын

    23 minute video has cost me my entire 8 hours of sleep, thanks.

  • @thomasrichard7054
    @thomasrichard7054Ай бұрын

    Very good! The result is remarkably close to sqrt(3)/3, so numerical integration may fool us. 😁

  • @keyaanmatin4804
    @keyaanmatin4804Ай бұрын

    4:37 is so relatable

  • @johnanderson290
    @johnanderson29029 күн бұрын

    Wow Kamaal, this was a beautiful beast! Most impressive! 👏

  • @emanuellandeholm5657
    @emanuellandeholm5657Ай бұрын

    I believe the term "King's Property" is an expression used by speakers of Indian English. At least I've never seen it being used by a native US/UK English speaker.

  • @sanamite

    @sanamite

    16 күн бұрын

    Interestingly enough, I've just read it in a french instagram post too ! What term do US/UK native speakers usually use to name it?

  • @emanuellandeholm5657

    @emanuellandeholm5657

    16 күн бұрын

    @@sanamite I guess they call it a "change of variable". It's interesting to me that the idiom exists in French. "King's property" sounds like royal real estate to me. :D

  • @juniorcyans2988
    @juniorcyans298827 күн бұрын

    This is a cool problem worth trying out. Thanks a lot!

  • @Mathematician6124
    @Mathematician612428 күн бұрын

    It's very easy using fourier series. I got it 😊. Dear Friend

  • @txikitofandango
    @txikitofandango28 күн бұрын

    I understand how you did the integration by parts, but I can't imagine myself ever escaping from uv - integral of v du paradigm

  • @mcalkis5771
    @mcalkis5771Ай бұрын

    Look at that, the gang's all here. I guess e and γ didn't get the invite though. And I suppose Ω isn't really friends with anyone these days. Although at this point I fully trust that you would be able to find an integral whose value contains everything. π, e, γ, G, ζ(3), ln2

  • @Anonymous-Indian..2003
    @Anonymous-Indian..2003Ай бұрын

    I guess i solved that question some weeks ago.🤔 But i didn't remember the book in which I've found that. Btw, your solution is also amazing. Love❤ you bro !(No HOMO)

  • @Anonymous-Indian..2003

    @Anonymous-Indian..2003

    Ай бұрын

    I remembered now, I solved by simplifying. Integral Term is: Int(0 - π/2) (x²/2) { tan(x/2) + tan(π/4 - x/2) }dx = Int(0 - π/2) (1/2) { x² + (π/2 - x)² } tan(x/2) dx Now it'll be easy, Substitute, (1/2)tan(x/2) = sinx - sin2x + sin3x - sin4x + ......... And booooom.

  • @yoav613
    @yoav61329 күн бұрын

    Very nice!

  • @CM63_France
    @CM63_France29 күн бұрын

    Hi, I am going to make a catalog of all these constants or functions defined by series, because I do not know them. "Terribly sorry about that" : 0:07 , 3:58 , 4:03 , 4:11 , 5:39 , 12:49 , 14:41 , 14:45 , 16:37 , 17:51 , 22:27 , "ok, cool" : 4:11 , 7:11 , 9:12 , 14:55 , 15:36 , 17:04 , 18:53 , 20:23 .

  • @maths_505

    @maths_505

    29 күн бұрын

    Wow there were alot in this video

  • @CM63_France

    @CM63_France

    28 күн бұрын

    @@maths_505 Yes, and you can notice that at 4:11 I spotted them both, the reason for this is that, at this time, you said something about my counting, unfortunately I don't understand what, but it ends with "thank you very much", or some thing like that, so I'm not that worried 😃. It's a pleasure for me. By the way could you make a video about the alternate ways(1) of prooving that zeta(2)=pi^2 / 6 . There is one that starts from int_0^infty { int_0^infty { dx dy / (1-xy) }} that is not that easy, because it involves a couple of variable substitutions a bit tricky. (1) otherwise than the famous Euler proof.

  • @MrWael1970
    @MrWael197029 күн бұрын

    There are some simple mistakes, but overall is very smart solution. Thank you indeed.

  • @sarahakkak408
    @sarahakkak40818 күн бұрын

    Great solution, but you was can use king rule in the first step

  • @romanvolotov
    @romanvolotovАй бұрын

    the amount of missing du's in this one is insane lmao

  • @hewhomustnotbenamed5912
    @hewhomustnotbenamed591227 күн бұрын

    8:08 We can take comfort in the fact that you're speaking from experience.

  • @PritamDas-zu9im
    @PritamDas-zu9im18 күн бұрын

    sir i think there is a mistake in 9:17 .you forgot to write cosine of log. its ln(cos{pi/4-u})

  • @txikitofandango
    @txikitofandango28 күн бұрын

    Didn't think a math video could be so salty :-p Result is very close to (error less than 0.1% of) the Euler-Mascheroni constant as well as the others mentioned

  • @christophercalvaire2014
    @christophercalvaire2014Ай бұрын

    from ln(1+tan u),we could expand to series with bernoulli number at once

  • @christophercalvaire2014

    @christophercalvaire2014

    Ай бұрын

    or I =int x ln (1+ tan au ) dx,using feymann trick, but it seems that I got an much simpler solution through this ode, I am not sure if I am right.dI/da=C-I*2/a

  • @malino0527
    @malino052725 күн бұрын

    Could you make a video about the integral from 0 to infinity of 1/(x^ln(x))? The result is the fourth root of e times the square root of pi, which I think is really beautiful. It seems that it uses the error function, if you plug it into wolframalpha you'll see.

  • @kingzenoiii
    @kingzenoiiiАй бұрын

    F, definitely watching cuz i have no friends 😭

  • @maths_505

    @maths_505

    Ай бұрын

    (with musical effects) you've got a friend in me

  • @kingzenoiii

    @kingzenoiii

    Ай бұрын

    @@maths_505 🤩

  • @maxvangulik1988
    @maxvangulik1988Ай бұрын

    now factor the result in terms of pi

  • @Aditya_196
    @Aditya_196Ай бұрын

    😂 I understand the nomenclature being kings rule like it's something great but in reality and significance it's just simple , idk myself why they say it maybe something like chess related where u swap King and took just moving around, it helps a lot in problem solving despite being so simple

  • @mihaipuiu6231
    @mihaipuiu623129 күн бұрын

    Sir math 505,...I try to understand a very nice integral from "a deceivingly difficult integral" and I met a formula, which I couldn't find proof. If you are kind to help me find this demonstration, because I can't continue to watch your integral.the formula is...ln(cosx) in terms of cos(2kx). Thank you very much for your help.If you agree to help the beginners like me to locate on the internet formula that you use without proof. This will be a huge help for people like me.I'm engineer and for me math is a HOBBY. Again thanks.

  • @maths_505

    @maths_505

    29 күн бұрын

    kzread.info/dash/bejne/n6WEtth-fK22fZM.html

  • @insouciantFox
    @insouciantFox29 күн бұрын

    Delicious

  • @aravindakannank.s.
    @aravindakannank.s.Ай бұрын

    F

  • @DestroManiak
    @DestroManiakАй бұрын

    How is it deceivingly difficult lol, it definitely looks difficult.

  • @maths_505

    @maths_505

    Ай бұрын

    It honestly looks kinda innocent....throw in an x² and a couple trig functions....and then you question all your life decisions leading up to that point 💀

  • @xdShaty
    @xdShaty29 күн бұрын

    i got roasted but it was true.. F

  • @mohammedfarhaan9410
    @mohammedfarhaan941029 күн бұрын

    F