Second order homogeneous linear differential equations with constant coefficients

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  • Опубліковано 8 бер 2017
  • This differential equation tutorial will cover the method of solving differential equations with constant coefficients. This is an example of auxiliary equations with distinct roots.
    Check out my differential equation playlists for more lessons and tutorials: www.youtube.com/@blackpenredp...
    4 popular ways to factor trinomial: • 4 popular ways to fact...
    🍎 Support me on patron / blackpenredpen
    #differentialequation #math #blackpenredpen

КОМЕНТАРІ • 155

  • @jellybabiesarecool4657
    @jellybabiesarecool4657 3 роки тому +22

    Some people make this stuff seem so complicated but when you explain it it's so simple.

  • @jamesvarner7816
    @jamesvarner7816 6 років тому +238

    Why is he carrying a Halo plasma grenade?

    • @naseemgharibi
      @naseemgharibi 5 років тому +11

      lol

    • @morrism6743
      @morrism6743 5 років тому +8

      It's a mic

    • @okami4133
      @okami4133 5 років тому +1

      Why you ask things nonsense?

    • @Jazoopi
      @Jazoopi 4 роки тому +31

      @@okami4133 hes speaking the language of the gods

    • @billh1337
      @billh1337 4 роки тому +2

      Make sure you pay attention

  • @tahukediri6388
    @tahukediri6388 2 роки тому +17

    this is beautiful, my lecturers never explain the origin of the identity equation (ar²+br+c) and here i am fascinated

  • @jhn9108
    @jhn9108 5 років тому +26

    wow!
    factoring the quadratic equation was really an amazing technique.

  • @yamunanagaraj8961
    @yamunanagaraj8961 6 років тому +36

    thank you man...
    this video really helped me

  • @juanvalencia1415
    @juanvalencia1415 4 роки тому +7

    your videos are insanely clear and easy to follow!

  • @cristinamendozar
    @cristinamendozar 5 років тому +6

    This was a really nice explained video, I appreciate the time you have taken to do it! Thank you :)

  • @suellenalmeida3040
    @suellenalmeida3040 3 роки тому +20

    I'm a Brazilian Student.Thank you so much! Your explanation helped me a lot :D

  • @irisce2799
    @irisce2799 5 місяців тому

    your videos are the best BPRP! I learned all of these techniques in math classes at universities where most of the course was focused on teaching these techniques and solving tons of practice problems through rote memorization, but now that I'm in my upper level engineering classes and starting to need to recall these techniques, I remember none of them because I never learned the underlying reasons behind the techniques! Watching your videos gave me understanding that I never had before, all packed in short form video content. Now I understand them and won't forget how to solve them. Super super valuable to me. Thank you!

  • @robinamar6454
    @robinamar6454 3 роки тому +13

    Thanks a ton for posting logically relevant videos which present the real flavor of mathematics instead of the dumb, dry & non-connected list of formulas which is taught in the high school to majority of the students!
    Please keep on preparing new videos on other key topics of mathematics!
    Thanks again :)

  • @Kicsa
    @Kicsa 2 роки тому +4

    I have an exam this weekend, I think after watching your methods i'll be more confident in my work, thanks!

  • @007myzorro
    @007myzorro 5 місяців тому

    FORMIDABLE ce que fait ce garçon. Toujours limpide et d une clarté et intelligence sans pareille. Merci à ce GRAND MONSIEUR !!!!😊😊

  • @mmka5434
    @mmka5434 6 років тому +3

    You are a very nice man and your teaching is really interesting! I appreciate your explanation! Thanks a lot!

  • @JesusGarcia-ox3jj
    @JesusGarcia-ox3jj 7 років тому +5

    I agree please do more differential equations questions.

  • @taekwondotime
    @taekwondotime 4 роки тому +15

    I wish he would put *all three cases* in the same video. Also, a lot of people may find that using the *quadratic formula* is much easier and less error prone than factoring, and it always works whereas factoring does not. The first time you run into one of these problems on an exam they'll probably stick you with something that doesn't factor OR you'll get a problem that has imaginary numbers in it, so this case is the most ideal case you can possibly get, but prepare yourself for something much nastier on an exam. :)

    • @blackpenredpen
      @blackpenredpen  4 роки тому +8

      Hey I actually have it here ua-cam.com/video/u-eQaef1EWw/v-deo.html

    • @taekwondotime
      @taekwondotime 4 роки тому +3

      @@blackpenredpen Thanks. Love your videos. Clear and to the point. :)

  • @abdinahmed6860
    @abdinahmed6860 2 роки тому

    simple yet comprehensive. Thank you :)

  • @cesarvillegas4626
    @cesarvillegas4626 2 роки тому

    By far the best video about this topic I have ever seen!!!

  • @lLl-fl7rv
    @lLl-fl7rv 3 роки тому

    From Canada, I say thank you very much man!!! You saved my life

  • @fatiswealth7865
    @fatiswealth7865 5 років тому

    what a genius this guy is!!! that factoring method is super useful

  • @JalenHill1321
    @JalenHill1321 3 роки тому +2

    Beautiful explanation!

  • @dabachinno1425
    @dabachinno1425 3 роки тому

    Thank you so much for the video. It helped so much!

  • @HairyPotter2006
    @HairyPotter2006 6 років тому

    Simply brilliant!

  • @rucha9610
    @rucha9610 5 років тому +1

    I LOVE YOU YOURE SAVING MY LIFE

  • @lizlaurens93
    @lizlaurens93 3 роки тому

    Thank you so much. The explanation was excelent.

  • @pahularora9642
    @pahularora9642 4 роки тому

    needed it so much...Thanks a lot...

  • @aleksjabraka8126
    @aleksjabraka8126 6 років тому

    I studied all the chapter but i forgot it, maybe bcz i did not exercise but your videos made me remember everything and so logically! Thank you!!

  • @williamkoleszar3301
    @williamkoleszar3301 3 роки тому

    brilliantly clear

  • @joelrodriguez1232
    @joelrodriguez1232 4 роки тому

    Excellent explanation.

  • @user-oz4qt7hl4g
    @user-oz4qt7hl4g Рік тому +1

    This man is amazing !

  • @ceciliachipulu5828
    @ceciliachipulu5828 2 роки тому

    Beautiful explanation

  • @emilgoubasarian9822
    @emilgoubasarian9822 2 роки тому

    You are legendary. Thank you so much.

  • @mohammadalawad8174
    @mohammadalawad8174 6 років тому

    Amazing bro... Thanks 🤗🤗🤗

  • @noonesherem8782
    @noonesherem8782 3 роки тому

    oh my god. dude you are a legend!!! i spent all day trying to figure this out because my textbook didn't explain it hahaha thank you

  • @FF-ie6sd
    @FF-ie6sd 5 років тому +3

    for those who wondering why y has to be equal to e^rt, here's my approach: FIRST!! Since it's a linear equation, y cannot have any power higher than 1. You might think it what if y=some constant, but then y' will be equal to 0, and so is y''. So if y = constant, then the whole equation becomes : a*0+b*0+cy=0 , then c =0. But the constants "abc" are always given, if c has to equal to 0, then the question will be like this: 0=0, which is lmfao. SECOND!!!, since it's a linear DE, then y cannot be inside of any function, for example, ln(y), sin(y), etc. Then it leaves only one thing that remains non-zero after million times of differentiation: e^rt, where r is a constant.

  • @nucspartan321
    @nucspartan321 2 роки тому

    Thank you!

  • @tombartimtim1725
    @tombartimtim1725 4 роки тому

    Thanks professor great job

  • @hervekalundu2978
    @hervekalundu2978 6 років тому +2

    I like the simple way of factoring!

    • @kaziaburousan166
      @kaziaburousan166 5 років тому

      notehelp.ga/2018/09/04/higher-order-differential-equations/

  • @neorenny5153
    @neorenny5153 4 роки тому

    Well explained Gud man.... Thank You.

  • @natashanatasha7875
    @natashanatasha7875 6 років тому

    thank you!

  • @unkown814
    @unkown814 7 років тому +3

    Thanks for the video, in response to the reply you sent me, I think it is worth trying some different upload frequencies to see how you grow. Maybe try grouping videos together based on A-level modules e.g. All chapters of fp2, to try and target more students as an audience

  • @eduardoandrescontrerasrome6703
    @eduardoandrescontrerasrome6703 2 роки тому

    Legend, thanks!

  • @whobegone
    @whobegone 3 роки тому +1

    u are a freakin G my friend, thank you

  • @MichaelKhaimraj
    @MichaelKhaimraj 7 років тому +11

    You should do a video on Wronskian's! I just learned them but they're a tad bit confusing. I'm not really sure why we use the solutions' derivatives in them.

  • @PressAltF4plz
    @PressAltF4plz 2 місяці тому

    Thanks!

  • @zeeraki
    @zeeraki 2 роки тому

    amazing teacher

  • @xandersteyn6398
    @xandersteyn6398 4 роки тому

    Thank you.

  • @johnjeffersonebergado7496
    @johnjeffersonebergado7496 4 роки тому

    Thanks man

  • @abderrahmanegouasmi7556
    @abderrahmanegouasmi7556 Рік тому

    Gréât. Thank you

  • @Sitanshu_Chaudhary
    @Sitanshu_Chaudhary 5 років тому +5

    Why we let e^rt if we use x^n there is any problem in question please reply to me

  • @oyedokun
    @oyedokun Рік тому

    Determine the most general function M and N such that the equations M(x,y)dx + (2xy³-x⁴y)dy is exact.

  • @akimbofennec5368
    @akimbofennec5368 3 роки тому

    Thanks bro

  • @tomatrix7525
    @tomatrix7525 3 роки тому

    BestpenStevepen, thank you

  • @sumantapanigrahi3765
    @sumantapanigrahi3765 5 років тому

    My best teacher

  • @ProtoMaxoid
    @ProtoMaxoid 3 роки тому

    You explain this better than my professor

  • @markjames4068
    @markjames4068 5 років тому +3

    Do you have a video for your "tic tac toe" method of factoring? If not, is there a name for this method so I can look it up myself? I have been doing it on my own with some success but I want to learn how to do it with a level of mastery.

  • @Askjeves
    @Askjeves 5 років тому

    The BOSS!

  • @tommyrosendahl7238
    @tommyrosendahl7238 6 років тому +65

    This is a really advanced episode of Dora the Explorer...

  • @naeemghafori5046
    @naeemghafori5046 5 років тому +3

    sir, I will gift you a wireless mic for these amazing tutorials

  • @ianmoseley9910
    @ianmoseley9910 5 років тому

    Could this be extended to any order DE =0?

  • @HoucineBenslimane-yq4mq
    @HoucineBenslimane-yq4mq 2 місяці тому

    what if we dont have the last y whats the results would be like in these example (y"+8y+16)

  • @haris525
    @haris525 6 років тому +2

    Hello
    Could I use the same method to solve this ODE - X''+𝝺X = 0, assume that e^(ax) is a solution
    thanks

  • @aarondelacruzruiz3416
    @aarondelacruzruiz3416 6 років тому

    Gracias chinito

  • @tinomsakwa3757
    @tinomsakwa3757 5 років тому +4

    could you have done this with a trig function or a normal polynomial?

    • @skylardeslypere9909
      @skylardeslypere9909 5 років тому

      y'' + y = 0
      You could use exponentials too, but in this one,
      y=sinx and y=cosx satisfy the equation too

  • @saleemshaya67
    @saleemshaya67 Рік тому

    Thanls

  • @TrolleningIshraq
    @TrolleningIshraq 4 роки тому +8

    Is there a proof that e^x is the only function with the property of being a constant of its derivative?

    • @faris1257
      @faris1257 4 роки тому +3

      If you solve the differential equation with this property y’=ay you find that the general form of any function that solves it must be Ce^(ax) so the only solution is e^ax with any coefficient multiplied in front so there is also the trivial solution y=0 but no distinctly separate function.

    • @me_hanics
      @me_hanics 4 роки тому

      also yes, it comes from the Taylor series of a function too
      Only c*e^x can have the same derivative

  • @prashant5737
    @prashant5737 2 роки тому

    Nicely explained👌
    Btw which pokemon is there in the pokeball that you're holding

  • @chritophergaafele8922
    @chritophergaafele8922 4 роки тому

    Can you do A lecture series on Multivariate calculus

  • @catnip2906
    @catnip2906 2 роки тому

    When you factor r^2-5r-6=0 does it matter which factor r=2 or r=-3/4 comes first?

  • @jordabox
    @jordabox 3 роки тому +1

    But when r are equal or delta is negative what happens?

  • @Jaws2525
    @Jaws2525 4 роки тому +3

    What if the the equation was equal to a constant instead of zero?

    • @pianoforte17xx48
      @pianoforte17xx48 4 роки тому

      Subtract the constant from both sides of equation to have the right side equal to zero.

  • @aashsyed1277
    @aashsyed1277 3 роки тому

    5:31 his favorite quadratic equation

  • @finalpurez
    @finalpurez 2 роки тому +1

    Not all heros wear capes

  • @adamfarihin6901
    @adamfarihin6901 4 місяці тому

    Hi, i don't understand 2 things:
    1) why did you multiply c1 and c2 to the general solution?
    2) why did you add the two solutions to make a general solution?

  • @user-go2yu4hq5p
    @user-go2yu4hq5p 4 роки тому

    is this Variation of Parameters or undetermined coefficient?

  • @omjoglekar3677
    @omjoglekar3677 3 роки тому +2

    5:10 whaaat ????
    what equation ?

  • @shaikmasthanvali5476
    @shaikmasthanvali5476 4 роки тому +1

    how Y=Epower RT

  • @lakshithasasindu6934
    @lakshithasasindu6934 4 роки тому +1

    I cant understand under the Frist example you right cross equation

  • @oryankibandi3556
    @oryankibandi3556 3 роки тому +1

    how do you find solve for the constants

    • @carultch
      @carultch 9 місяців тому

      You would need to know two initial conditions, or conditions at a known t-value (other than zero). Usually initial conditions.
      For his example with the solution:
      y = C1*e^(-3/4*t) + C2*e^(2*t)
      Suppose you were given y(0) = 1, and y(1) = 0.
      You'd construct two versions of this equation, based off this information.
      1 = C1*e^0 + C2*e^0
      0 = C1*e^(-3/4*1) + C2*e^(2*1)
      Solve for C1 and C2
      C1 = e^(11/4)/(e^(11/4) - 1)
      C2 = 1/(1 - e^(11/4))

  • @Oscar-jg9gg
    @Oscar-jg9gg 10 місяців тому

    so im trying to understand the general solution of the beam bending theory for a column... any advice? the solution is in terms of sine and cosine and im not sure what happens to the imaginary number...

    • @Oscar-jg9gg
      @Oscar-jg9gg 10 місяців тому

      nvm. i just figured out that the assumed solution is just y=Acosrx + Bsinrx as opposed to y=Ae^rx1+Be^rx2

  • @sambamenba6908
    @sambamenba6908 3 роки тому

    Is it possible to find out c1 and c2? I know they're arbitrary, but I would like to know if there's a way to find them out.

    • @adityaekbote8498
      @adityaekbote8498 3 роки тому

      I think you will need some kind of initial value

  • @user-go2yu4hq5p
    @user-go2yu4hq5p 4 роки тому

    please answer me what is this method's name you are using at the begining ????

    • @carultch
      @carultch 9 місяців тому

      The method of the ansatz.

  • @zuhayrdalwai1107
    @zuhayrdalwai1107 4 роки тому

    What happens if the roots of the quadratic equation are complex?

    • @carultch
      @carultch 9 місяців тому

      If the roots of the quadratic are complex, it means the solution is a linear combination of sine and cosine, that are enveloped by an exponential decay.
      Two real and distinct roots means the solution is a linear combination of two exponential functions of different rates.
      y(t) = A*e^(r1*t) + B*e^(r2*t)
      A repeated real root means the solution is a linear combination of e^(r*t) and t*e^(r*t).
      Pure imaginary roots, of -b*i and +b*i, mean the solution is a linear combination of sin(b*t) and cos(b*t).
      Complex conjugate roots of a-b*i and a + b*i, means the solution is e^(a*t)*(A*cos(b*t) + B*sin(b*t)).

  • @ananthakrishnank3208
    @ananthakrishnank3208 5 місяців тому

    Smooth even at 2x speed

  • @Ahmed-vs1ui
    @Ahmed-vs1ui 2 роки тому +1

    Why do we assume that y is an exponential function cant it just be a polynomial as well?

    • @carultch
      @carultch 9 місяців тому +1

      Because exponentials have derivative patterns that repeat, while polynomials have derivative patterns that annihilate. Therefore, in order to have a differential equation that is a linear combination of a function and multiple levels of its derivative, it has to be an exponential.
      The solution will contain polynomial terms, if there is a polynomial on the right side of a non-homogeneous equation. It still will either have an exponential or trigonometry, as its fundamental solution.

    • @EgzoDiuse
      @EgzoDiuse 9 місяців тому

      @@carultchthanks a bunch this question was really bugging me

  • @tomeraviram6594
    @tomeraviram6594 3 роки тому

    Sometimes it looks like -9y and not like =9y because of the strong light

  • @shaikmasthanvali5476
    @shaikmasthanvali5476 4 роки тому

    what about unequal roots,complex roots ,equal roots ,coordinate roots

    • @carultch
      @carultch 9 місяців тому

      Unequal roots = linear combination of exponential functions of different growth/decay rates.
      Repeated roots = linear combination of e^(r*t) and t*e^(r*t)
      Imaginary roots = linear combination of sine and cosine
      Complex conjugate roots = linear combination of sine and cosine, that is enveloped by an exponential function. Real part tells you the exponential rate constant, and imaginary part tells you the sine and cosine frequency.

  • @mohrezshaikh4091
    @mohrezshaikh4091 6 місяців тому

    you should have that mic for giveaway

  • @aka0989
    @aka0989 5 років тому

    why is e never zero ? you must assume that r > 0 first bc e^(-∞) = 0 right ?

    • @iaagoarielschwoelklobo1894
      @iaagoarielschwoelklobo1894 4 роки тому +4

      well, not quite. For e^(-x) you get 1/e^x, which never is zero either. Be careful with e^(-∞), because ∞ cannot be used in a function like a number. You can indeed say that the limit lim x->-∞ (e^x) = 0, because the limit describes the behaviour of the function (in this case getting arbitrarily close to 0 as x decreases). But the value of the function itself is never "truly" zero. I hope that satisfies your question.

  • @stewartmoore5158
    @stewartmoore5158 5 років тому +8

    Why the microphone orb tho...

    • @brandonc3231
      @brandonc3231 4 роки тому +1

      it is drip. for the seductive appeal

  • @johnk3841
    @johnk3841 6 років тому

    What if the roots are imaginary?

  • @felicytatomaszewska2934
    @felicytatomaszewska2934 4 роки тому +1

    Why are you holding a ball in your hand? Nice tutorial :)

    • @carultch
      @carultch 9 місяців тому

      It's his microphone

  • @someone5895
    @someone5895 6 років тому +28

    Thats some nice ice on my nigga's wrist.

    • @knightwik
      @knightwik 4 роки тому +1

      dont say nigger, its racist

  • @idreesi.m.m5973
    @idreesi.m.m5973 6 років тому

    دەست خوش

  • @EgzoDiuse
    @EgzoDiuse 9 місяців тому

    the bird of hermes is my name

  • @marianmortada8978
    @marianmortada8978 5 років тому +2

    why y equal to an exponential

  • @xxxprawn8374
    @xxxprawn8374 4 роки тому

    but i don’t think you proved that the function has to be exponential?

  • @5anatakos
    @5anatakos 5 років тому

    some comments
    1. Too many explanations - one can do it in half the time
    2. How about solving it without any suggest?
    3. How about suggesting a trigonometric or a polynomial or a logarithmic or a combination of these?

  • @Metalhammer1993
    @Metalhammer1993 7 років тому +1

    stupid question. what would you do about a 3rd order? like 3y'''-3y''+2y'-5y-2=0 ? without the 2 and the 5y I'd just say if i integrate i have a second order easy peasy but like this? i have no clue

    • @herbcruz4697
      @herbcruz4697 6 років тому

      Metalhammer1993 You need to first add 2 to both sides. Then solve it as if it was a homogeneous differential equation, so set the characteristic polynomial equation equal to zero (0) and solve for r. The characteristic polynomial is 3r^3-3r^2+2r-5. Use the rational roots theorem, and do synthetic division to find the first root. Doing so results in a quadratic equation, which you can solve by either factoring (if factorable), completing the square, or using the quadratic formula. That will give you the complementary solution. Then use the method of undetermined coefficients to find the particular solution. The general solution will be equal to the complementary solution plus the particular solution. In disguise, this is really a non-homogeneous differential equation with constant coefficients.

  • @tjalle3627
    @tjalle3627 10 місяців тому

    well well well

  • @michaelcampbell2390
    @michaelcampbell2390 3 роки тому

    goat