Solving a Quick and Easy System of Differential Equations

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  • Опубликовано: 5 ноя 2024

Комментарии • 63

  • @WahranRai
    @WahranRai 2 года назад +5

    Chain rule : y+1 = dy/dt = (dy/dx)*(dx/dt) = (dy/dx)*xy --->
    Separation : (y/y+1)*dy = (1-1/(y+1))dy = dx/x ---->
    Integration : y - ln(|y+1| + c1 = ln(|x|) + c2 ---> x = +- c3*e^y / (y+1)

    • @SyberMath
      @SyberMath  2 года назад +2

      You're missing the point. The idea is to solve for x and y in terms of t

  • @Adventurin_hobbit
    @Adventurin_hobbit 2 года назад +11

    Please can you make a video about mastering Mathematics from the beginning and suggest books to read and study , and I hoped. If you can give recommendations for IYMC

    • @me0449
      @me0449 2 года назад +1

      what field of math are u interested in

    • @Adventurin_hobbit
      @Adventurin_hobbit 2 года назад +2

      @@me0449 see I am a high school student at grade 10 , so the most branch of mathematics I concerned with it is precalculus , Trigonometry and Algebra. I intended to participate in IYMC , so I wanted to learn skills like making a mathematical proof , logic and problem solving, so I needed a book that I can start with. Further more When I had a look at the branches of mathematics I found they were too many , so I confused and I didn't know which branch should I start with , some people told me to start with discrete mathematics and others told me that discrete mathematics isn't important for you and I should start with prealgebra, so I am really confused.

    • @aashsyed1277
      @aashsyed1277 2 года назад

      What is IYMC?

    • @Adventurin_hobbit
      @Adventurin_hobbit 2 года назад +1

      @@aashsyed1277 International youth mathematics competition.

    • @buxeessingh2571
      @buxeessingh2571 2 года назад +2

      Start with Geometry Revisited by Coxeter. I also recommend finding Kiran Kedlaya's PDFs online for more training.

  • @Blaqjaqshellaq
    @Blaqjaqshellaq 2 года назад +1

    If you consider x in terms of y, you get x=p*e^y*e^(1-t)
    And if you consider y in terms of x, you get y=q*ln(x) + t - 1
    (p and q being two more constants)

  • @captainkarma7374
    @captainkarma7374 2 года назад +4

    Thanks for these videos, im a 10th grader but learn a lot from these videos!

  • @shmuelzehavi4940
    @shmuelzehavi4940 2 года назад

    The second equation, dy/dx = y + 1 may be transformed into: dz/dx = z (where z=y+1). This is a standard first order linear homogeneous o.d.e, which has a classic general solution: z = C exp(t) , or :
    y = C exp(t) - 1.

  • @broytingaravsol
    @broytingaravsol 2 года назад +1

    x=c1e^(ce^t-t), y=ce^t-1

  • @andrejivonin2133
    @andrejivonin2133 2 года назад +2

    y=-W(C/x) - 1

  • @atingupta77
    @atingupta77 2 года назад

    Please make a video on integration and related short trickx

  • @ahmadmazbouh
    @ahmadmazbouh 2 года назад

    this concept is new to me

  • @MichaelJamesActually
    @MichaelJamesActually 2 года назад

    It's a beautiful day when I get the answer and I use your same methodology.

  • @antonyqueen6512
    @antonyqueen6512 2 года назад

    Substitute z=y+1
    => dz/dt = z
    => z = k*e^t
    => y = k*e^t - 1

  • @aashsyed1277
    @aashsyed1277 2 года назад

    Great syber !!!!!!!

    • @SyberMath
      @SyberMath  2 года назад

      Thanks, aash! Long time, no see 😄

  • @kinshuksinghania4289
    @kinshuksinghania4289 2 года назад

    Would it be wrong if I got rid of the parametric independent variable t??

    • @angelmendez-rivera351
      @angelmendez-rivera351 2 года назад

      Yes, if only because, even if you find an equation relating x and y directly, you still need to constrain what x and y can be by solving the differential equations.

  • @kushaldey3003
    @kushaldey3003 2 года назад

    I was thinking we would eliminate t and solve y in terms of x.
    Divide the 2 equations
    dx/dy = xy/(y+1)
    => dx/x = ydy/(y+1)
    => lnx = c + y - ln(y+1)
    => x = n*(e^y)/(y+1)

  • @rajeshbuya
    @rajeshbuya 2 года назад

    Wouldn't it be a lot simpler to start off by dividing the 2nd equation by the 1st equation? That would get rid of't' and just have dy/dx in terms of the variables 'x' and 'y'.

    • @fredthelegend7673
      @fredthelegend7673 2 года назад

      Agreed

    • @shmuelzehavi4940
      @shmuelzehavi4940 2 года назад +1

      Not necessarily in this case.
      In my opinion, solving the equation: dy/dx = (y+1) / (xy) is not simpler than solving the given system as it is.

    • @SyberMath
      @SyberMath  2 года назад

      You need to find x and y in terms of t, not y in terms of x

    • @fredthelegend7673
      @fredthelegend7673 2 года назад

      @@SyberMath Ohhhh ok that makes more sense, thanks 👍

    • @rajeshbuya
      @rajeshbuya 2 года назад

      Got it@@SyberMath . Thanks for clarifying the problem statement. Please continue to inspire us with such challenges.

  • @Ne-us3pj
    @Ne-us3pj 2 года назад

    Bazı şeyleri anlamlandırmamda çok yardımcı oldu, emeğinize sağlık :)

    • @SyberMath
      @SyberMath  2 года назад +1

      Sevindim. Tesekkurler!

  • @SuperYoonHo
    @SuperYoonHo 2 года назад

    thanks🙃

  • @me0449
    @me0449 2 года назад

    the bounds of integration(notation)
    was easy but nice 👍

    • @SyberMath
      @SyberMath  2 года назад +1

      Glad you liked it!

  • @omograbi
    @omograbi 2 года назад +1

    The solution can be more simpler I guess.
    If we separate dt and equate the the dt of both sides. I ended up with [y=((k-x)/x))]

    • @GirishManjunathMusic
      @GirishManjunathMusic 2 года назад

      Inyour case, dy/dt = -k(k - x)/x², which doesn't satisfy the given value of dy/dt = y + 1.

    • @omograbi
      @omograbi 2 года назад

      @@GirishManjunathMusic I think you've diffrentiate in respective for y, you should apply implicit differentiation for both y and x.

    • @GirishManjunathMusic
      @GirishManjunathMusic 2 года назад

      @@omograbi I differentiated y wrt t like you're suppsoed to do for a separated equation like this.

    • @pwmiles56
      @pwmiles56 2 года назад +2

      Given
      dx/dt = xy [1]
      dy/dt = y+1 [2]
      Divide [2] by [1]
      dy/dx = (y+1)/(xy)
      This is separable:
      dy y/(y+1) = dx/x
      dy [1 - 1/(y+1)] = dx/x
      Integrate both sides, take a constant into ln(x)
      y - ln(y+1) = ln(kx)
      Solve for x
      x = exp(y) /[k(y+1)]
      You can get x as a function of y, but not easily vice versa. Anyway the problem is asking for x and y as functions of t. Conceptually we are working on the (x, y) plane. The point (x, y) moves according to [1] and [2].

    • @omograbi
      @omograbi 2 года назад +1

      @@pwmiles56 yes that's correct, thank you, I misscalculated the integration.

  • @patrick-8068
    @patrick-8068 2 года назад

    dx=xy*dt
    define​ d​ is​ HOUR.
    dx = HOUR​ basic.
    dx​ = 1​ o'clock.
    xy*dt = 1
    second in​ 1​ o'clock
    dt​ is​ second​ by​ inlaw Sine0
    dt=3600
    xy*3600 = 1
    xy=1/3600=0.1 sec
    inlaw​ paspal dy/dt​ is​ minute
    dx/dt​ is​ second
    x=0.1/minute
    y​ = 1​ was​ time
    0.1=1+1=2
    0.1=2 Answer.

  • @hsshashidhargowda4349
    @hsshashidhargowda4349 2 года назад

    Why u took "e" on both side

  • @tbg-brawlstars
    @tbg-brawlstars 2 года назад +1

    I can't understand this video cuz I haven't started Differentiation and Integration yet 😅

    • @SyberMath
      @SyberMath  2 года назад +1

      Now is the time!

    • @tbg-brawlstars
      @tbg-brawlstars 2 года назад +1

      @@SyberMath It will be started in like November or something
      But I have done some basics of both

    • @chandrashekharmehta6121
      @chandrashekharmehta6121 2 года назад +1

      @@tbg-brawlstars 12 me ho n abhi aap
      Jee k liye prepare kr rhe ho may be..

    • @tbg-brawlstars
      @tbg-brawlstars 2 года назад +1

      @@chandrashekharmehta6121 Abhi Boards chal rahe hai....11th mei nhi aaya but still thoda bahut kar liya aage ka
      And Yes JEE prep

    • @chandrashekharmehta6121
      @chandrashekharmehta6121 2 года назад +1

      @@tbg-brawlstars Ohh nice yarr 🌟😀👍

  • @barakathaider6333
    @barakathaider6333 2 года назад

    👍