The Easiest Integral on YouTube

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  • Опубліковано 13 сер 2017
  • He did the derivative!!! Check out Fematika • Checking BlackPenRedPe...
    100 integrals: • 100 integrals (world r...
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    blackpenredpen

КОМЕНТАРІ • 1,3 тис.

  • @blackpenredpen
    @blackpenredpen  5 років тому +630

    OK, I checked the answer and it was correct! ua-cam.com/video/mUXdgY5MeEg/v-deo.html
    Happy New Year!!!

    • @notnilc2107
      @notnilc2107 5 років тому +8

      I approve.

    • @alexsanders7303
      @alexsanders7303 5 років тому +2

      Lol, just finished the vid and relaised this

    • @marziyaali7962
      @marziyaali7962 4 роки тому +1

      Oh god my maths test is on 1st Aug and I haven't prepared for it yet...... integrals is also in test!😢😢😢

    • @pongwang9893
      @pongwang9893 4 роки тому +1

      thanks , the integral is really amazing. so intelligent.
      Mathematics is deeply bottomless, and probability and statistics are more difficult to understand.
      Gamma distribution, chi-square distribution, is so hard to understand.

    • @sahlileila6382
      @sahlileila6382 4 роки тому

      i really need your help to intigrate this for me i really need it ----- x-1*sqrt.2x-x*2
      /x+1

  • @wellbangok8959
    @wellbangok8959 6 років тому +4807

    Somewhere out there, a professor is gonna watch this video and make this problem a test question. RIP.

    • @davidkippy101
      @davidkippy101 6 років тому +147

      Sheev Palpatine Saw the comment, liked for the name

    • @blackpenredpen
      @blackpenredpen  6 років тому +473

      Sheev Palpatine I just had to pin this comment.

    • @levi4328
      @levi4328 6 років тому +144

      oh no, don't give them ideas

    • @sorryperson92
      @sorryperson92 6 років тому +104

      Sheev Palpatine that would be acceptable if that was an extra credit question where if you get it right you get full credit for the exam

    • @user-bv3ed1cn7w
      @user-bv3ed1cn7w 6 років тому +29

      Sheev Palpatine did you ever hear the tragedy of darth plagueis the wise?

  • @BT7M
    @BT7M 6 років тому +2686

    You know it's a hard problem when he has to use 3 colors

    • @blackpenredpen
      @blackpenredpen  6 років тому +187

      BT7M yup

    • @isaacormesher2851
      @isaacormesher2851 6 років тому +199

      blackpenredpenbluepen

    • @Anonymous_Poetry
      @Anonymous_Poetry 4 роки тому +28

      This is not hard prblm we indians take 30 sec to solve this

    • @booga9584
      @booga9584 4 роки тому +2

      @@g.peloni3694 none cause we never and then we're like wtf are we doing.

    • @midhun.m4963
      @midhun.m4963 4 роки тому +1

      @@g.peloni3694 uff...😂I'm also An Indian I'm a Calculus Lover too...

  • @AviMehra
    @AviMehra 6 років тому +2142

    Check the answer by differentiation

  • @friendofjim
    @friendofjim 6 років тому +903

    I don't want you to check your answer by differentiation. I want you to integrate your answer :D

  • @yoavcarmel1245
    @yoavcarmel1245 6 років тому +475

    8:15 *erases that additional line*
    ohh god thank youu

  • @flansterr
    @flansterr 6 років тому +482

    I think you did a step wrong somewhere, please differentiate it to check.

  • @davidkippy101
    @davidkippy101 6 років тому +527

    You're going from blackpenredpen to 3blue1brown

    • @blackpenredpen
      @blackpenredpen  6 років тому +175

      How so? His vids are way cooler

    • @Number3pt14
      @Number3pt14 6 років тому +73

      Because this is really REALLY complicated yet you manage to explain it so well. Its cool at the same time

    • @davidkippy101
      @davidkippy101 6 років тому +50

      blackpenredpen Because of the color markers you are using

    • @blackpenredpen
      @blackpenredpen  6 років тому +90

      blackpenredpen and sometimes blue : )

    • @NoNameAtAll2
      @NoNameAtAll2 6 років тому +29

      blackpenredpenbluepengreenpen

  • @andresvivas2814
    @andresvivas2814 6 років тому +775

    when you say "please do not ask me to check the answer by diferentiation", I'm pretty sure you were really thinking "please ask me to check the answer by diferentiation" ... So, in order to please you..... Would you check the answer by diferentiation???? Please :)

    • @blackpenredpen
      @blackpenredpen  6 років тому +173

      lol! I am waiting for some viewers to do it!

    • @manuelbonet
      @manuelbonet 6 років тому +47

      blackpenredpen We want you to check it by differentiation. It's always easier than the integration, right?

    • @monzur1947
      @monzur1947 6 років тому +28

      blackpenredpen I proved it using my calculator. Is that good enough?

    • @aysikl
      @aysikl 6 років тому +10

      scrolled down expecting the comment "check the answer by differentiation" as top or only comment ..
      urs was 3rd and has a bunch of text around it
      internet, you disappoint......
      (altho the expectation ur not meeting, is actually... so in a way.... yay! ....)

    • @blackpenredpen
      @blackpenredpen  6 років тому +23

      Maybe?!

  • @rileywells3045
    @rileywells3045 6 років тому +327

    This is probably the most fun I've ever had watching a video about integrals! It was a long journey, but it was worth every second. Thankyou for such a great video!

    • @blackpenredpen
      @blackpenredpen  6 років тому +18

      Riley Wells my pleasure!!!!

    • @leif1075
      @leif1075 Рік тому

      @@blackpenredpen But why on earth would you do that second substitution at all? Isn't there another way maybe more intuitive..like integration by parts Ibwas thinking..Hope you can respond when you can.

  • @shakirahsanromeo7863
    @shakirahsanromeo7863 6 років тому +394

    I fear you may run out of substitute variables one day :P

    • @blackpenredpen
      @blackpenredpen  6 років тому +78

      Shakir Ahsan Romeo probably. Next I will use alpha, beta

    • @iconoptixx
      @iconoptixx 6 років тому +71

      *creates new alphabet after using all latin, greek, cyrillic, hebrew and arabic letters*

    • @Queenhideyxo
      @Queenhideyxo 5 років тому +11

      Evolution can you give me more letters for my substitions into different integral worlds?
      Sure blackpenredpen
      ACTUALLY USES OLD LETTERS FOR SUBSTITUTIONS LIKE A BOSS

    • @arnavanand8037
      @arnavanand8037 4 роки тому +12

      After that start using ♤♡◇♧¤▪☆

    • @hamiltonianpathondodecahed5236
      @hamiltonianpathondodecahed5236 4 роки тому +7

      How about हिन्दी

  • @maxhaibara8828
    @maxhaibara8828 6 років тому +554

    I have a challenge for you. Make the generalization of the integral of n-th root of tan x dx

    • @kamarinelson
      @kamarinelson 6 років тому +50

      I was wondering this myself lol at the beginning of this video. I'm betting it inevitably leads to just letting u= the n-th root of tan(x) and then integrating the resulting rational function using partial fraction decomposition - maybe synthetic division for powers of tangent not = 1 or 2.

    • @kamarinelson
      @kamarinelson 6 років тому +21

      of course, I'm ignoring any possible trig manipulations ...

    • @eroskuikel9688
      @eroskuikel9688 5 років тому +15

      This should be easy. Separate tan^n into tan^(n-2) and tan^2 then integrate by parts. Then substitute sec^2-1 for tan^2 and you get a reduction formula. Evaluate integral of tan^2 and that should be enough I guess.(I havent tried this but I think this works for even exponents only.)

    • @eroskuikel9688
      @eroskuikel9688 5 років тому +2

      Kyro well Oh yeah..

    • @surenmoodley7744
      @surenmoodley7744 3 роки тому +3

      Lol that's sadistic!

  • @tipoima
    @tipoima 6 років тому +33

    30:40 "Please, do not ask me to check the answer by differentiation"
    Hey, you should totally check the answer by differentiation!

  • @natalieeuley1734
    @natalieeuley1734 6 років тому +93

    I love this. Great example of when to actually use partial fractions, too. I'm adding this channel to my list of favorite math channels! 🤓🤓🤓

  • @blackpenredpen
    @blackpenredpen  6 років тому +7

    He did the derivative!!!!!!!!!!!! Check out Fematika's
    ua-cam.com/video/as1vk0IuAHA/v-deo.html

  • @JoJoJet100
    @JoJoJet100 6 років тому +27

    Doctor: You have 31 minutes and eight seconds to live.
    Me: immediately opens this video

  • @loganmancuso3791
    @loganmancuso3791 6 років тому +151

    Ok to the one dislike on the video I want you to post a follow up showing everyone how you do this integral.

  • @mr.gentlezombie8709
    @mr.gentlezombie8709 6 років тому +90

    Now do the integral of (tanx+(tanx)^(1/2)+(tanx)^(1/3)+(tanx)^(1/4)+(tanx)^(1/5)...)

  • @12345678910111213796
    @12345678910111213796 6 років тому +140

    Can you check the answer by differentiation ?

    • @blackpenredpen
      @blackpenredpen  6 років тому +19

      Pedro Bessa maybe one day :)

    • @nationalstudyacademykim5030
      @nationalstudyacademykim5030 4 роки тому +1

      Really quick way to check. Takes 30 seconds. Plug in some values the the limit of integration and use fund. Thm of calc p2.

  • @bonbonpony
    @bonbonpony 6 років тому +41

    16:56 Yeah, putting down some TNT on that would definitely help :)
    18:18 It's quite interesting that `1/2` and `√3/2` appear in the completed square, because:
    a) they are the real and imaginary part of the cube root of `-1` that appear in the complex factorization of the denominator;
    b) they are the sine and cosine of the 60° angle at which this cube root lays with respect to the real axis :)
    c) we've got the cube root (of the tangent) in the original integrand.
    21:30 We have to go deeper... :>
    23:52 The dream is collapsing :J

    • @blackpenredpen
      @blackpenredpen  6 років тому +7

      Ah!!! I like the pt u made at 18:18... and what u said "The dream is collapsing"

  • @ianbo1
    @ianbo1 6 років тому +111

    Worth every second of the watch. Thank you!

  • @azmath2059
    @azmath2059 6 років тому +11

    Now that is just incredible! By far one of the most difficult integrals I have ever seen and you have solved it so elegantly and so well.

  • @Xperia347
    @Xperia347 6 років тому +114

    Could you check the answer by differentiation?

  • @sethleverett8889
    @sethleverett8889 3 роки тому +24

    Video: “Easiest integral on UA-cam”
    Me: oh that’s nice let’s check it out
    Also video: equation is written very small and 31 minutes
    Me: oh no...

  • @particleonazock2246
    @particleonazock2246 3 роки тому +36

    This problem was soooooo easy! I solved it when I was a foetus. Hats off to this young gentleman realising the foetal power of solving integrals!

    • @lih3391
      @lih3391 2 роки тому +3

      Fetus?

    • @JMZReview
      @JMZReview Рік тому +4

      Bro really spelled it with an o 💀

    • @General12th
      @General12th Рік тому

      @@JMZReview diarrhoea

  • @Kreighzey
    @Kreighzey 6 років тому +41

    30:40 differentiASIAN

  • @void2509
    @void2509 4 роки тому +44

    Imagine doing a test and solving this problem. You did every step right, but you forgot to write plus C

    • @delta2884
      @delta2884 3 роки тому +8

      And professor deducts 1mark for that

    • @invasion8318
      @invasion8318 3 роки тому +6

      @@delta2884 my professor would tear the whole thing and give you 0 ;)

    • @dzlcrd9519
      @dzlcrd9519 2 роки тому +1

      Easier when in France they ask for a antiderivative so you don't have to add +C

    • @user-lh5hl4sv8z
      @user-lh5hl4sv8z 2 роки тому

      Calc II + Calc II

  • @X-3K
    @X-3K 6 років тому +348

    what about the tan(x) root of tan(x)?

    • @nestorv7627
      @nestorv7627 6 років тому +42

      I think impossible

    • @aceeternus4027
      @aceeternus4027 6 років тому +24

      NestorV S I thought you could integrate anything you wanted

    • @RubALamp
      @RubALamp 6 років тому +96

      Ace Eternus no, there are functions that their integral have no solution. A classic example of this is the function f(x)=e^x^2.

    • @mh-no5it
      @mh-no5it 6 років тому +59

      Ace Eternus
      Some functions have no elementary anti derivative take x^x for example, you have to settle for a series.

    • @sinistrolerta
      @sinistrolerta 6 років тому +43

      Gregory House Tecnically there is a solution, but it just can't be expressed in terms of exponentials, polynomials, logarithms etc

  • @ATeamBrown
    @ATeamBrown 6 років тому +8

    This couldn't have been uploaded at any time better, I'm just about to fall asleep and I always trance at your videos which makes me go to sleep! Thank you so much! :D

  • @malayagr
    @malayagr 2 роки тому +8

    The second integral can be done without any substitution:
    Multiply and divide by 2 (you can factor out the divide by 2 later, with the final constant distribution):
    (2t+2)/(t²-t+1)
    The derivative of the denominator is 2t-1. So, write the integral as:
    (2t-1+3)/(t²-t+1)
    Split the fraction:
    (2t-1)/(t²-t+1) + 3/(t²-t+1)
    The first one's integral is ln|t²-t+1|. For the second one, complete the square as (t-1/2)²+(√3/2)². The integral is 2√3*invtan((2t-1)/√3).
    Now, distribute the divide by 2:
    1/2*ln|t²-t+1|+√3*invtan((2t-1)/√3).

  • @howtoglobal7901
    @howtoglobal7901 4 роки тому +1

    i just love your videos man... i just want to say that you helped me overcome my fear of integrals.. and your approach to not just this video but all the others are just brilliant.. thank you.

  • @dovidglass5445
    @dovidglass5445 3 роки тому +1

    I love how enthusiastic you are! What great videos you make.

  • @stanschimerman
    @stanschimerman 5 років тому +7

    Fantastic job of explaining every step!

  • @rohitg1529
    @rohitg1529 6 років тому +19

    Please differentiate this to get back to cuberoot of tan x

  • @MRBYRNO2505
    @MRBYRNO2505 5 років тому +1

    you are such an amazing teacher you make this advanced stuff seem so easy

  • @Fematika
    @Fematika 6 років тому

    I did the differentiation! Find it here! ua-cam.com/video/as1vk0IuAHA/v-deo.html

  • @mathematically4761
    @mathematically4761 2 роки тому +9

    I thought he will forget the + C part
    Truly professional to the core
    I am starting to fall in love with math and pens
    And of course our one and only
    *CALCULUS*🥳🥳

  • @eveliohernandez6595
    @eveliohernandez6595 6 років тому +5

    i never´ ve seen a intgral like this
    . i been watching all your videos and in my opinion is very useful. in other side i want to thank, you videos are helping me to improve my english how you know ,y native language is spanish, but thanks for share it. congrats

    • @blackpenredpen
      @blackpenredpen  6 років тому

      Thank you so much. I am very happy to hear your nice comment! Keep up the good work too!

  • @vynderma
    @vynderma 4 роки тому

    Glad you enjoyed yourself with that. This is a great review of a lot of techniques.

  • @hendrickdias8366
    @hendrickdias8366 6 років тому +1

    Watching this made me very relaxed. You sir deserve a subscribed!

  • @jeffreycanfield1939
    @jeffreycanfield1939 6 років тому +44

    I'm worried for you.

    • @blackpenredpen
      @blackpenredpen  6 років тому +71

      MistaTwoJeffreyTwenty Yaay
      U should worry about my students

    • @jeffreycanfield1939
      @jeffreycanfield1939 6 років тому +8

      blackpenredpen oh noooo, show them sympathy please, they don't deserve this!

    • @blackpenredpen
      @blackpenredpen  6 років тому +2

      Lol! I am teaching a calc2 class in the fall. We will see!! : )

    • @JorgetePanete
      @JorgetePanete 6 років тому

      blackpenredpen the next year i will see integrals on our tests and i need a bless from Pitagoras to pass these exams

    • @Metalhammer1993
      @Metalhammer1993 6 років тому

      if they´re not nice they get this integral on their exam! how about that? or worse sin(x)/x from 0 to infinity (but don´t ask for the steps. that´s overkill. though maybe you can show us that one? i didn´t see a single video on YT about that ntegral i would have understood. and the only idea to even make this possible would be using the mclaurin series of the sine)

  • @clementtan5004
    @clementtan5004 6 років тому +112

    here i am watching 30 minutes of math porn and not knowing wtf is going on

    • @kibayuuto6634
      @kibayuuto6634 6 років тому +17

      Clement Tan isn’t that the case when watching regular porn too?

    • @suyunbek1399
      @suyunbek1399 5 років тому

      Жиза

  • @nashli5789
    @nashli5789 4 роки тому

    You're videos are awesome! Please keep posting :)

  • @angelogandolfo4174
    @angelogandolfo4174 2 роки тому

    That was a really enjoyable lil’ video. Thank you, it was a nice little refresher! 🙂

  • @DreamzAnimation
    @DreamzAnimation 6 років тому +13

    please check the answer by differentiation

  • @LightYagami-on5lm
    @LightYagami-on5lm 5 років тому +71

    When title says easy and time says half an hour
    🤔🤔🤔🤔🤔🤔🤔😱

  • @taarchi
    @taarchi 6 років тому

    An excellent video, explained clearly. Really enjoyed watching the video and even had a try myself after watching. Great job.
    我非常喜欢这个视频关于积分。黑笔红笔老师的解释清楚!看到了这个视频我自己试一试解决这个积分!

  • @davidgillies620
    @davidgillies620 4 роки тому +1

    It's also expressible in terms of "the" hypergeometric function 2F1.

  • @bonbonpony
    @bonbonpony 6 років тому +9

    Can you make some videos about the strategies of choosing the right integration technique for different problems?

  • @AviNash6817
    @AviNash6817 6 років тому +7

    Good. this is a high level problem in my sheet .

  • @Harothir
    @Harothir 6 років тому +1

    This is just what I needed for my summer.

  • @Ben_747
    @Ben_747 6 років тому

    Great video! Have you ever done a video on something like integrating root(lnx) or the something of the sort? My favourite of your videos are ones like these, after having a go and failing miserably it's nice to see I wasn't missing anything *too* obvious haha XD Keep up the great work!

  • @vj_henke
    @vj_henke 6 років тому +37

    This channel is now offically a MATH MEME !
    "How about the integral of [fancy variation of sqrt(tan x)] ?" - bprp, you have a long meme carrier ahead...

    • @blackpenredpen
      @blackpenredpen  6 років тому +11

      oscarjd74 OH WOW!!!! YOU ACTUALLY DID IT!

    • @vj_henke
      @vj_henke 6 років тому +3

      NEAT, instant screen saver ^^

    • @caducoelho2221
      @caducoelho2221 6 років тому +1

      How cool iz dat?! HAHAHAH

  • @BlackFiresong
    @BlackFiresong 6 років тому +3

    I kept on making mistakes when trying to check this answer by differentiation, and had pledged to keep this video tab open until I had successfully checked it. So pleased to say that I finally got it right today! I can close the tab now. :D

    • @blackpenredpen
      @blackpenredpen  6 років тому +1

      BlackFiresong wow nice!!! I will check it one day too.

    • @BlackFiresong
      @BlackFiresong 6 років тому +1

      Thank you so much for replying! Love your work. :) Please do keep the crazy challenges coming. You have really helped to rekindle my love of Maths!

    • @blackpenredpen
      @blackpenredpen  6 років тому +1

      BlackFiresong I am very glad as well!! Thank you for watching my videos :)

  • @saultube44
    @saultube44 6 років тому

    Thank you dude, your explanation is very good, efficient, to the point, best of lucks

  • @chessandmathguy
    @chessandmathguy 6 років тому +1

    very very good video and very satisfying to have a clean solution in the end.

  • @sirfactor
    @sirfactor 6 років тому +5

    You earned yourself a new sub
    Thanks sir .

  • @JBaker452
    @JBaker452 6 років тому +9

    This does turn out to be a monster of an integral "doesn't it" :-)

    • @blackpenredpen
      @blackpenredpen  6 років тому +2

      Yea, isn't it?!

    • @JBaker452
      @JBaker452 6 років тому

      So how does the monster grow in the complex domain?
      I would love to see the secrets in there so that I might apply them to quantum mechanics (and my cool design for a new warp drive model).

  • @kirkjungles4901
    @kirkjungles4901 6 років тому +2

    Wow, impressive stuff. How did you initially learn to solve it? Copious amounts of time and errors? Experience just gives you the intuition to know when/where/what to substitute and what steps to take? More than anything, I'm just curious how people like you navigate through problems like these. On my old calc 2 exam, there were relatively difficult problems, but I could kinda just look at em and get a feel for how to solve it in my mind, but this seems like way too much to do a mental run through from start to finish.
    Either way, great video.

  • @jeffersonluizbento20
    @jeffersonluizbento20 5 років тому

    Cara, impressionante! Parabéns pela loucura de resolvê-la.

  • @ulilulable
    @ulilulable 6 років тому +3

    This is so great! I wish I still had the "mathematical muscle" to do this myself. Maybe one of these days...

    • @thelegendofme7520
      @thelegendofme7520 2 роки тому +2

      Hey man just checking in, its been 4 years hows that math muscle working out for you? I challenge you to do 3 integrals! You can do it

    • @ulilulable
      @ulilulable 2 роки тому

      @@thelegendofme7520 Aaany day now... ;)

  • @tavishu
    @tavishu 4 роки тому +3

    Great, now integrate (tanx)^1/5

  • @meraldlag4336
    @meraldlag4336 10 місяців тому

    I'm so happy to see a "BIG INTEGRALS NO SHORTCUTS" playlist, will watch them all

  • @NWSCS
    @NWSCS 6 років тому +1

    The interesting thing would be a professor taking the solution of that integral and making the class find the derivative maybe as a bonus problem on an exam.

  • @philmertens2673
    @philmertens2673 6 років тому +44

    Please make a video about the nth root of tanx

    • @timedilatesme
      @timedilatesme 6 років тому +5

      yes i agree

    • @dicandeo9698
      @dicandeo9698 6 років тому +3

      Yes, that'd be great! :)

    • @sunriselp849
      @sunriselp849 6 років тому +5

      I want to see that too

    • @jiaming5269
      @jiaming5269 6 років тому +4

      tan(nx) ^ (1/n)

    • @angelmendez-rivera351
      @angelmendez-rivera351 6 років тому +1

      I want to see this too, although I'll try it myself first because it may be possible that it be not expressible in terms of elementary functions or with a finite definite expression.

  • @citizenalex1934
    @citizenalex1934 6 років тому +4

    "When in doubt, use horseshoe mathematics."

    • @craftbuzzwonky4752
      @craftbuzzwonky4752 3 роки тому

      You too saw the video!!
      I see, you are a man of "NO U" culture here!

  • @theadri_zero7057
    @theadri_zero7057 6 років тому

    I love your videos!!

  • @timedilatesme
    @timedilatesme 6 років тому +1

    seems like a deep breathtaking moment when you got the answer to be this long...

  • @Zhardamon
    @Zhardamon 6 років тому +3

    pure beauty...!

  • @kylefarias9143
    @kylefarias9143 6 років тому +13

    do the integral of sqrt(tan(cuberoot(tanx)))

    • @nejlaakyuz4025
      @nejlaakyuz4025 5 років тому

      Kyle Farias Just use numerical integration on given bounds

  • @KrisEditz29
    @KrisEditz29 5 років тому +1

    Most elegant integral I've seen so far,thank you sir

    • @ktuluflux
      @ktuluflux Рік тому

      Nothing even remotely elegant about this. This is the equivalent of opening a safe by dropping an anvil on it.

  • @andrecouverette
    @andrecouverette Рік тому

    Best problem ever!
    Tour de force for methods of integration.
    I counted eight different tricks.
    TI-84 plus showed it correct over:
    -2π

  • @benjaminbrady2385
    @benjaminbrady2385 6 років тому +4

    I was kind of hoping to see you dancing in celebration chanting "One Take!" at the end

    • @xamzx9281
      @xamzx9281 6 років тому +1

      who knows maybe its 10th take

    • @blackpenredpen
      @blackpenredpen  6 років тому +1

      Notice that I didn't edit this video!

    • @markzero8291
      @markzero8291 6 років тому +1

      MrQuantum "one take" and "1st take" are different.

    • @blackpenredpen
      @blackpenredpen  6 років тому +4

      Mark Zero true. One take for this tho. I think it was my 3rd take bc my intros weren't good enough.

    • @xamzx9281
      @xamzx9281 6 років тому +1

      Mark Zero k

  • @sunglow9835
    @sunglow9835 5 років тому +4

  • @prollysine
    @prollysine 3 роки тому

    Gratulálok, ez a szinte végig helyettesítéses módszer bemutatta, hol kezdődik az elméleti matematika !

  • @BRUBRUETNONO
    @BRUBRUETNONO 6 років тому +2

    Tumbs up for this ace demonstration !!!

  • @ronnykazadi559
    @ronnykazadi559 5 років тому +3

    Can you do integral of (xtanxdx) ?

  • @Centauri902
    @Centauri902 6 років тому +5

    now the nth root

  • @Magic73805
    @Magic73805 6 років тому

    You are really great sir.

  • @johnmichael91
    @johnmichael91 6 років тому +1

    Pretty cool and nicely done! May i request to make a video about integrals of non elementary functions like e^cosx? Very much appreciated if you would.

  • @roceb5009
    @roceb5009 6 років тому +3

    Okay so you've done sqrt tan x, you've done cube root tan x, can you generalize? Nth root tan x ?

  • @TheKillerSock
    @TheKillerSock 6 років тому +3

    yea dog imma need you to check by differentiation

  • @jihanhamdan5465
    @jihanhamdan5465 6 років тому

    To solve for B and C in partial fraction decomposition do the same as u did for A but find for that expression a complex root, substitute then compare

  • @enriquevanegas5741
    @enriquevanegas5741 5 років тому

    Jesus Christ! With this you have won a new follower! Subscribed!

  • @LucBogaert
    @LucBogaert 6 років тому +7

    Running a marathon is easy compared to solving this integral 🤓

  • @jousif650
    @jousif650 6 років тому +13

    It is too long, not too hard. Anyway I doubt anyone can do it in any exam without making a small mistakes ☺

    • @blackpenredpen
      @blackpenredpen  6 років тому +9

      it's like running a marathon (well, almost...)

  • @mutenfuyael3461
    @mutenfuyael3461 Рік тому +1

    For B in 11:45, I like to multiplie by t in both side, and by going in the limit in +infini, we have 0=A+B

  • @kummer45
    @kummer45 Рік тому

    Standard integrals are square root of tangent x, tangent x elevated to 1/3 and so on like tangent x elevated to 1/4. The exercise gets extremely complicated when we consider powers of 1/5 and so. I think that tangent to the 1/2 and tangent to the 1/3 are fair practice problem for assignments covering almost every technique in integration.
    This is a good exercise for substitution, partial fraction, determinants and the Gauss Jordan elimination method. It has the classical strategies and the knowledge of well known integrals including the logarithmic ones.

  • @Bludgeoned2DEATH2
    @Bludgeoned2DEATH2 6 років тому +3

    Dr. BalckPenRedPen, please check the answer by differentiation :)

  • @capjus
    @capjus 6 років тому +76

    You can't impress a girl with it

    • @bmc868
      @bmc868 6 років тому +48

      sure it's too smart for them....

    • @timstorer978
      @timstorer978 6 років тому +62

      I disagree. Perhaps your trying to impress the wrong girls.

    • @azmath2059
      @azmath2059 6 років тому +6

      No you can't impress the girls quite true, but you can impress them with the money you make if you're working in this particular field.

    • @General12th
      @General12th 6 років тому +40

      If you can't impress your girl with this stuff...
      *you're not talking to the right girls*

    • @bmc868
      @bmc868 6 років тому +3

      Almost all girls like money, luxury cars and spending time shopping. They want M-O-N-E-Y......and their math skills is +....+money+money+money......

  • @maxwongpt2channel328
    @maxwongpt2channel328 6 років тому

    This is awesome! Never seen such integral before :O

  • @filibus31
    @filibus31 6 років тому +1

    I have tested to diferenciate on geogebra and it works !!
    Cool video !!

  • @thewatcherinthecloud
    @thewatcherinthecloud 6 років тому +5

    ...And when you want to take a break from listening to this video, you are going to SUBSTITUTE IT for one of the easier/more beautiful ones to understand :D Like sin(z)=2

  • @Far_Gem
    @Far_Gem 6 років тому +53

    It kinda bothers me that you write "tan^-1" instead of "arctan", it makes it seem like you could get tan^-(1/3) by multiplying it with tan^(2/3).

    • @MC-mx1mt
      @MC-mx1mt 6 років тому +2

      Florian Bender if you mean 1/tan x, he would write it as cot x

    • @monzur1947
      @monzur1947 6 років тому +14

      Florian Bender tan^-1 is a standard notation for arctan

    • @GrouchierThanThou
      @GrouchierThanThou 6 років тому +29

      I agree. It's bad form IMO to both use tan^-1(x) for arctan(x) as well as the tan^q(x) for (tan(x))^q within a single exercise.

    • @angelmendez-rivera351
      @angelmendez-rivera351 6 років тому +9

      Monzur Rahman We're aware, but it's a terrible notational standard.

    • @GrouchierThanThou
      @GrouchierThanThou 6 років тому +2

      It's not even a "standard" notation really. Just a commonly used one (and not even as commonly used as the arctan notation).

  • @hachemimokrane2810
    @hachemimokrane2810 3 роки тому

    excellent travail ! Explication en détail

  • @gaspberries8445
    @gaspberries8445 7 місяців тому

    For anyone wondering, the constant to make them equal is pi * sqrt(3) /12

  • @robertherbert8419
    @robertherbert8419 6 років тому +5

    ....It wasn't that bad....it didn't have limits to substitute (hehe ! )

  • @factsheet4930
    @factsheet4930 6 років тому +4

    And then you look at the footage, and you realize you didn't press record...

  • @DavideCosmaro
    @DavideCosmaro 5 місяців тому +1

    25:49 let's all appreciate how his only mistake in the video was using the wrong coloured marker

  • @matteolorusso5523
    @matteolorusso5523 5 років тому +1

    Wolfram Alpha says" you goddamn right boy"