Power Series Solution for a differential equation

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  • Опубликовано: 3 янв 2025

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  • @csegura26
    @csegura26 5 лет назад +131

    The first second of this video is really remarkable

  • @damian.gamlath
    @damian.gamlath 6 лет назад +105

    definitely cool.
    I love your way of teaching because you address the little doubts along the way, and explain why we are doing something, and why it makes sense to even think about doing it in the first place..
    Something that alot of other youtubers don't do as well as you do. Thank-you :)

    • @blackpenredpen
      @blackpenredpen  6 лет назад +9

      27kdon I am glad to hear that! Thank you.

    • @ameerzain6857
      @ameerzain6857 3 года назад

      you all probably dont care at all but does someone know of a trick to log back into an Instagram account..?
      I was dumb forgot the password. I love any tricks you can give me!

    • @btiabdes
      @btiabdes Год назад

      222222222222222222222222222222222222222222222222222222

  • @Acoustic_Mutale
    @Acoustic_Mutale 8 месяцев назад +108

    2024 Engineers where you at?

  • @HolyHubcap
    @HolyHubcap 7 лет назад +63

    Did anyone else notice his awesome 1 handed marker switching skills? Great video, very helpful !

  • @Arycke
    @Arycke 7 лет назад +66

    I have a degree in mathematics and I would have to say that it is always good that two methods yield the same answer for a problem 👍the power series derivation I'm sure will help those seeking to understand how to find a power series solution to a differential equation :D plus power series are so important in analysis so this is a good introduction to that as well. Great video!

    • @JoQeZzZ
      @JoQeZzZ 7 лет назад +1

      How have you never studied power series solutions to n-th order differential equations while getting your math degree?

    • @skateboarderlucc
      @skateboarderlucc 6 лет назад +11

      you misread...he said the video would be a good starting point for beginners (obviously not referencing himself).

    • @abda7184
      @abda7184 6 лет назад

      Thank you very much for this informative explanation 👌👌👌👍

  • @m.abdullah4518
    @m.abdullah4518 11 месяцев назад +4

    Bro your teaching method is goooood. Got my semester final today and this cleared power series for me which I wasn't able to understand the whole dam semester

  • @SuperDreamliner787
    @SuperDreamliner787 7 лет назад +10

    I´m currently attending a differential equations class and I have to solve one with the powers series method. Thank you for putting this up! Greetings from Germany! :)

  • @jammcrusader1981
    @jammcrusader1981 4 года назад +8

    dude honestly you are the man - i bought a shirt cause of how much you helped me

  • @randys2669
    @randys2669 11 месяцев назад +1

    Recently got back into studying math, this is such a beautiful method for differential equations

  • @seanfraser3125
    @seanfraser3125 7 лет назад +10

    I think its great that you can find the solution in two very different ways. Yes, obviously the power series analysis is much more involved, but it also shows you another way of finding the general solution to the ODE. One of my favorite things about math is that there is almost always more than one way to approach a problem and find the same solution.
    Of course, if the problem on an exam was to find the power series solution to the ODE, I would just find the exact solution and find its power series. Saves a few minutes :)

    • @blackpenredpen
      @blackpenredpen  7 лет назад +5

      Yea, I like it whenever we can solve a problem with multiple ways. This could also be done with integrating factor as well.

  • @ryujinryuk
    @ryujinryuk 7 лет назад +106

    19:40 when u activate the asian mode........

    • @marouanechokri3970
      @marouanechokri3970 5 лет назад +1

      LOL

    • @tomatrix7525
      @tomatrix7525 4 года назад

      But he is Taiwanese

    • @Hyperdrive
      @Hyperdrive 3 года назад

      @@tomatrix7525 Yeah Taiwan isn’t in Asia

    • @tomatrix7525
      @tomatrix7525 3 года назад +2

      @@Hyperdrive I just got a notifcation with ur reply. I have no recollection commenting that so Idk what I was thinking. Of course it is jn Asia

  • @Collinator02
    @Collinator02 Год назад +2

    this guy is single handedly teaching me diff eq. ive had 3 teachers so far. 1st dude i withdrew from, graded ridiculously hard. made up stuff that only he understood. talked in an accent and wouldn't help. 2nd and 3rd taught the class together split in the middle. 2nd guy was alright just ranted about random stories sometimes. 3rd guy. sheesh. tiny asian dude who whispers. cant understand a thing he says, and when he does talk about something really important he just starts talking 20 times faster WHILE STILL WHISPERING. love you blackpenredpen

  • @josemaringarcia3335
    @josemaringarcia3335 4 года назад +2

    Thanks for making the re-definition of powers so easy to follow.

  • @shayanmoosavi9139
    @shayanmoosavi9139 5 лет назад +3

    The power series solution is starting to click for me. Thank you very much :)
    P.S : 10:26 e cosine, e cosine, e cosine😁😁

  • @blackpenredpen
    @blackpenredpen  7 лет назад +91

    Hi!

    • @indrada-rf2vu
      @indrada-rf2vu 7 лет назад +1

      blackpenredpen hi :)

    • @batubulgur
      @batubulgur 7 лет назад

      blackpenredpen I just gave my math101 final and it went pretty well. Just learned Taylor and stuff like that. And seeing its usage to solve diff eq's is pretty cool. Love maths, still a lot to learn.
      I have a question, don't you have to calculate the remainder and show that it approaches zero? I mean, it looks just like e^x that gives us confidence but still...?

    • @jordancastaneda7027
      @jordancastaneda7027 7 лет назад

      "It's just like excel!" yes, yes it is indeed, thank you so much for helping me see it this way ! This is the easiest explanation I have came across so far.

    • @alienmoondudes8071
      @alienmoondudes8071 7 лет назад

      I laughed when seeing that xD

    • @lalitverma5818
      @lalitverma5818 6 лет назад

      Hi

  • @jennieferadombire926
    @jennieferadombire926 5 лет назад +2

    Thanks so much. I really enjoy your way of teaching, it makes the math so easy

  • @Skull2121
    @Skull2121 7 лет назад +1

    I needed this 4 days ago for my differenials final :,( i was searching all over youtube for a great video like yours! Keep it up!

  • @Ballzdippedincheese
    @Ballzdippedincheese Год назад

    You really helped me out i was stuck with this question for the past 5 or 6 minutes.....thank you

  • @EngSeifHabashy
    @EngSeifHabashy 11 месяцев назад

    Man I love how you save me!!❤❤
    I'm having my ODEs final exam after 2 days and I forgot all the methods and watching your videos right now

  • @hidude1130
    @hidude1130 7 лет назад

    Dude you're by far the most talented bloke i've seen in youtube

  • @gaming_boga
    @gaming_boga 5 лет назад

    Sir finally found a maths teacher in my life plz keep uploading videos thnks!!

  • @syaoransakura8839
    @syaoransakura8839 4 года назад

    Wow, thank you. Your explanation save my TASK

  • @ahmadalrjoub7352
    @ahmadalrjoub7352 11 месяцев назад

    thank you, Very clear and easy explanation

  • @KadeW10
    @KadeW10 6 лет назад

    Thank you so much! I was never any good with series solutions and this video helped me significantly! Thank you

  • @JacobKennedyowuor
    @JacobKennedyowuor 4 года назад

    Wonderful. This has made sense to me for the first time. Thank you @blackpenredpen. I am writing an exam on Monday for Planetary Physics. Power series has been a nightmare. Not any more.

  • @maryam_ahli
    @maryam_ahli 6 лет назад

    THANK YOU SO MUCH!!! literally this saved my life!!

  • @rosemarybereket
    @rosemarybereket 7 месяцев назад

    The you explain everything is so amazing ❤❤❤❤

  • @Prxwler
    @Prxwler 3 года назад +3

    Woah, I haven't finished my calc 1 course and I find the first method overwhelming. Seems cool to be able to understand it AND replicate it, but knowing the second method exists made me feel a little relieved lol

  • @Play-cn1ck
    @Play-cn1ck 7 лет назад

    Thank you for your detail explanation.

  • @axlortega2881
    @axlortega2881 9 месяцев назад +2

    why is a1 equal to zero at 6:33

  • @deligentchacha5420
    @deligentchacha5420 5 лет назад +1

    this guy is a genius. Its an automatic distinction if you practice with Blackpenredpen

  • @jayt675
    @jayt675 Год назад

    Awesome teacher!

  • @wagsman9999
    @wagsman9999 6 лет назад

    Love your videos. Very clear. Help me with my calculus tutoring. Thanks.

  • @usmanjaved2350
    @usmanjaved2350 5 лет назад

    Outstanding dear.... I cleared my every point... Love you dear ♥️♥️

  • @hichamitani6433
    @hichamitani6433 4 года назад

    excellent explanation: keep it up prof

  • @sjoerdwiesmeijer7231
    @sjoerdwiesmeijer7231 4 года назад

    That was really fun and insightful!

  • @hatsinze
    @hatsinze 9 месяцев назад

    Thanks for the explanation

  • @ostdog9385
    @ostdog9385 7 лет назад +3

    Awesome I love it

  • @amin2468
    @amin2468 7 лет назад +1

    Thanks alot, helpful as always.

  • @aylin_spg
    @aylin_spg 6 лет назад

    Thank you so much!!! You really help me
    I could understand it so well 👍

  • @codedragon6237
    @codedragon6237 7 лет назад

    Great videos! Keep it up!

  • @JoanneCheptoo
    @JoanneCheptoo 4 года назад

    Bless your heart.

  • @FrankMarquez-cc2ye
    @FrankMarquez-cc2ye 8 месяцев назад

    Thanks dude!!

  • @abdulrahmanalaqeel1720
    @abdulrahmanalaqeel1720 3 года назад

    the old way is about 1 million times better than this journey, thanks for the video very helpful.

  • @meedumdarshana1591
    @meedumdarshana1591 6 месяцев назад

    Thank You So Much

  • @davidhart1322
    @davidhart1322 7 месяцев назад

    Test in 5 hours. Thanks man.

  • @ВладКузь-з7ч
    @ВладКузь-з7ч 7 лет назад +22

    if only I saw this 3 weeks ago...

    • @Abdu_401
      @Abdu_401 5 лет назад

      I can feel the sad energy behind this comment ...

  • @willilow
    @willilow 3 года назад

    eres un crack amigo,, gracias ,, saludos desde Chile

  • @gamingwolf3385
    @gamingwolf3385 Год назад

    thank you a lot you are a great teacher , i love your style , and i start watching your videos instead of being present in my teacher boring classes hhh , i am kidding only , thank you a lot

  • @gregorio8827
    @gregorio8827 6 лет назад +2

    Doing this integrating (using dy/dx notation) is extremly easy

  • @emmanueladdo1430
    @emmanueladdo1430 7 лет назад

    this video helped me in my math exam...thanks alot

  • @araf-b
    @araf-b 2 года назад

    Just awesome 🥰❤️

  • @thobilesikakane6113
    @thobilesikakane6113 3 года назад

    You are the best at explaining the harder stuff. I wish you could do pdes, i guess its a bit late for me though.

  • @user-se1hj5vx3k
    @user-se1hj5vx3k 7 лет назад

    Very insightful

  • @albajasadur2694
    @albajasadur2694 4 года назад +1

    Sir, you showed in another video lecture that a Laplace transform is in fact a continuous analogue of Power series. By using this example, can you demonstrate and explain why it is more handy to solve this ODE by using Laplace transform ?

  • @hassanalihusseini1717
    @hassanalihusseini1717 7 лет назад

    A nice week to solve it with a power series, as power serieses are very important to make calculations easier.
    Of course it would be much faster to solve this problem by separation of variables:
    y' + 2xy = 0
    y/y' = -2x
    lny = -x^2 + c1
    y=ce^-x^2
    (with c := e^c1)
    I like your videos a lot, because they make me understand calculus deeper. Are you considering to make other videos on other subjects in mathematics, too?

  • @masterenglish7838
    @masterenglish7838 6 лет назад +2

    awsome
    i love your way of teaching...thank you

  • @drosos_strength_coaching
    @drosos_strength_coaching 3 года назад +1

    Proper video title: why not to solve differential equations with power series even if your life depends on it

  • @ennjoseph7311
    @ennjoseph7311 2 года назад

    You are really remarkable ,, if only we could meet ,,you've been of so much help

  • @chritophergaafele8922
    @chritophergaafele8922 4 года назад

    I never see you solve a math problem that fast

  • @MegaPruddy
    @MegaPruddy 4 года назад

    awesome 👏👏 👏

  • @pawankumarbehera2963
    @pawankumarbehera2963 11 месяцев назад

    you rock

  • @luckybruno5827
    @luckybruno5827 4 года назад

    Thank you so much, way better than my professor (:

  • @amandabrandao3266
    @amandabrandao3266 3 года назад

    this guy is a GOD

  • @peerless3538
    @peerless3538 3 года назад

    Awww you are so cute.....🥺.......thanks for the precious help......Almighty bless you.....🙌🏻

  • @Kurtlane
    @Kurtlane 7 лет назад

    Your videos are great, including this one. Just one correction; here you say several times "to compromise it." I'm not sure what is the right word here, maybe "to counterbalance it" or "to restore the original meaning," or something else, but it's definitely not "to compromise."
    It's not depressing, it's excellent!

    • @blackpenredpen
      @blackpenredpen  7 лет назад +1

      Kurtlane hi there! Thanks for the comment. My idea was like this: suppose u and I are making a deal, I give u two dollars, which means If i lose 2 then gain 2. Just like a trade. When I said this in my face to face class, my students understood it.

    • @oqardZ
      @oqardZ 7 лет назад +1

      Expression you are looking for is "to compensate for it".

    • @blackpenredpen
      @blackpenredpen  7 лет назад

      oqardZ that's for $ tho lol!

    • @blackpenredpen
      @blackpenredpen  7 лет назад

      oqardZ but I might also use that next time

    • @davidgould9431
      @davidgould9431 7 лет назад +3

      English can be a wretchedly difficult language. I am a 56 year old native speaker with only a rudimentary grasp of any second language, so I am totally in awe of people who manage to be 98% fluent in English, so please don't take this as a criticism of the videos: they are all perfectly understandable but, while we are talking about English rather than maths, I may be able to cast some light.
      The problem here is that compromise has gradually taken on two different meanings, depending on how it's used exactly (grammar alert: transitive versus intransitive usage):
      "to compromise *something* " means to make that something worse or to create a bad effect: if you have a container of water and you make a hole in it, you compromise its water retention (because it will leak). If you say that someone has a bad temper, or is lazy or something bad, you compromise their ability to get a job: you make it work less well. You might say you compromise *them* in that case.
      "to reach a compromise" or just "to compromise" (but no object: " we disagreed, but we compromised."), which is what you are doing with your trading example, is to make a deal that is part way between the two parties' starting positions: if I want to sell you my car for $1000 and you want to buy it for $500 we might compromise on $750. Or if I want to go to the cinema and my wife doesn't want to see the film, we might compromise by going out for a meal: we both get an evening out, but not our ideal evenings. As long as we both enjoyed it, we reached a good compromise.
      To wheel out some gratuitous grammar, when "to compromise" is transitive (that is, it takes an object: you compromise *something*), you are making that thing worse. When "to compromise" is intransitive (no object: you just compromise with each other, say), you are reaching an agreement.
      As oqardZ says, in this case a native speaker would use "to compensate": you have made a change in one place and, therefore, you need to make a change in another place to compensate for that first change.
      Sorry: this is far too long a comment. As I said initially, the videos are great and easy to understand: it's just that , in this case, what you said doesn't mean what you think it means.

  • @zavionw.8052
    @zavionw.8052 5 лет назад +2

    Me: *looks at thumbnail*
    Also me: "whitetextredtext"

  • @raphaelseitz805
    @raphaelseitz805 7 лет назад +2

    thanks a lot for your videos blackpenredpen :)
    the only point i did not get was why a1 has to be 0. couldn't it be anything?

    • @KorraAndVaatu
      @KorraAndVaatu 5 лет назад +1

      I also found it weird that we assumed a1 was 0

    • @souravchakraborty6766
      @souravchakraborty6766 Год назад

      It's zero bc the right hand side is 0. That is why he set everything to zero. I hope this helps ;)

  • @MirryKay
    @MirryKay 2 года назад

    Helpful

  • @inothernews
    @inothernews 7 лет назад +1

    Great video! I have not done power series solutions in a long while so this is a good refresher! May I know what your academic background is?

  • @charliewilson3234
    @charliewilson3234 6 лет назад

    Excellent stuff def not depressing.

  • @pratishamishra4142
    @pratishamishra4142 6 лет назад

    Thank u

  • @mokouf3
    @mokouf3 4 года назад

    It is the Normal distribution curve!

  • @zhylerliebesleid9771
    @zhylerliebesleid9771 4 года назад

    This is so interesting

  • @dreamking597
    @dreamking597 Месяц назад +1

    Depressing lol but still your amazing at teaching it

  • @dahazz
    @dahazz 7 лет назад +1

    Hey! Can you do an IVP and finding the singular points?
    THANKS!

  • @FuhrerShattercore
    @FuhrerShattercore 7 лет назад +1

    Will you be able to teach us the method of Frobenius? It just appeared in my Mid-term exam and I've concluded that my professor is a sadist... and that it will appear again the finals. Thanks for the video anyways. :D

  • @yifengwang790
    @yifengwang790 5 лет назад

    what a god

  • @kgotlelloramatsetse2162
    @kgotlelloramatsetse2162 3 года назад

    beyond cool!!!!!

  • @jay1435
    @jay1435 7 месяцев назад

    God bless you soldier

  • @cencenpolinar3085
    @cencenpolinar3085 2 года назад

    for the second equation isn't n = -1 to make it x^n? thanks

  • @xrisku
    @xrisku 7 лет назад

    I am watching this wondering why none of it looked quite familiar, until you did the old way. then a neural circuit instabtly lit up. :)

  • @levi4328
    @levi4328 7 лет назад +2

    why couldn't we just set the summation to be equal to -a1? 7:00

    • @hugocampos7894
      @hugocampos7894 4 года назад

      Perhaps a bit late but if I'm not mistaken it's because it's being multiplied by an X^n on the right and you can't really cancel that with anything inside the summation

  • @john-athancrow4169
    @john-athancrow4169 6 лет назад

    I liked you finally said a .

  • @sh6700
    @sh6700 3 года назад

    That is so cool!

  • @calebe16
    @calebe16 7 лет назад

    Power series are interesting in some specific cases.
    I would like to know how to do with power series for non homogeneous differential equation.

  • @charlesrothauser1328
    @charlesrothauser1328 4 года назад +1

    I find the youtube commercials during this video a terrible distraction

  • @hlamzar
    @hlamzar 6 лет назад

    you're awesome

  • @N8TheGr8M8
    @N8TheGr8M8 4 года назад

    Why do some people start the series at n=1 and some people start it at n=0 for the y' series?

  • @mehmetdemirel527
    @mehmetdemirel527 7 лет назад +1

    can you do videos about -1/12?

    • @blackpenredpen
      @blackpenredpen  7 лет назад +4

      should I?
      It has already been done by numberphile and others tho.

    • @nickstollard6205
      @nickstollard6205 7 лет назад

      masonery123 zeta(2) is beautiful, I did the proof in my calc class and my teacher said that it was a really cool proof. if you want to look at it yourself it's called the Basel problem

  • @manuelodabashian
    @manuelodabashian 7 лет назад

    I have always found the point where you get the x's to the same index difficult to understand how do you get the extra term?

    • @blackpenredpen
      @blackpenredpen  7 лет назад

      Manuel Odabashian which extra term?

    • @manuelodabashian
      @manuelodabashian 7 лет назад

      blackpenredpen when you set n=0 why are there three parts before there were two

    • @AndDiracisHisProphet
      @AndDiracisHisProphet 7 лет назад +1

      hm, you have to remember that this is still a sum, so instead of going sigma from n=0 you just look at n=0 separatly and then take sigma from n=1

    • @indrada-rf2vu
      @indrada-rf2vu 7 лет назад +1

      Manuel Odabashian the sum from n=0 to infinity of f(n) is the same as the sum from n=1 to infinity of f(n) +f(0)

  • @lorenzolevy4708
    @lorenzolevy4708 5 лет назад

    Can you hypothetically use series to solve any ODE?

  • @SomeOne-gh3tw
    @SomeOne-gh3tw 6 лет назад

    i LOVE U

  • @jarikosonen4079
    @jarikosonen4079 3 года назад

    a1=0 & series-sum=0, so it's all 0 then.
    But if series-sum=-a1, will it be all 0 then also?
    a1=5 & series-sum=-5, how would it work?
    Maybe nothing that need be proven.

  • @15jorada
    @15jorada 7 лет назад +1

    I'm a math major that is thinking about going to China to study abroad next summer. Do you work at a Chinese University? I would love to meet you. If not do you have any good recommendations for a Chinese University I could go to?

    • @anatomania1126
      @anatomania1126 7 лет назад +2

      15jorada Dude he works at UC Berkeley

  • @PeterBarnes2
    @PeterBarnes2 7 лет назад

    Would it be possible to do a power series with the differential equation y' - ylnex + ay/x - by/(xlnex) = 0? I think that might be a pretty cool problem.

  • @iamprodigyable
    @iamprodigyable 6 лет назад +2

    Im having trouble seeing how those two answers he found are equal to each other. I mean, I know they are, but i don't see it. can anyone explain?

    • @saraaxx9100
      @saraaxx9100 3 года назад

      he has used the separation of variables method for the second time.. which's another method of solving differential equations

  • @fountainovaphilosopher8112
    @fountainovaphilosopher8112 7 лет назад

    Is it possible to find a function so that *f'(x)+2xf(x)=1?*

    • @blackpenredpen
      @blackpenredpen  7 лет назад +1

      Ognjen Kovačević yes! Please see first order linear diff eq. I have a playlist here ruclips.net/p/PLj7p5OoL6vGwe4MSETi11Sa73CPD1JoCI

    • @fountainovaphilosopher8112
      @fountainovaphilosopher8112 7 лет назад

      If so, then the integral of e^(x^2) is possible.

    • @versionpatch
      @versionpatch 7 лет назад +1

      Just because the function exists doesn't mean it can be written in terms of elementary functions.

    • @fountainovaphilosopher8112
      @fountainovaphilosopher8112 7 лет назад

      cool

  • @digbycrankshaft7572
    @digbycrankshaft7572 3 года назад

    Nice

  • @w.a.domski
    @w.a.domski 6 месяцев назад

    watching this at 12am before my math test in 8am, and i haven't even studied power series yet (yes im an idiot), wish me luck