Why it doesn't converge to 3?

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  • เผยแพร่เมื่อ 5 ก.ค. 2024
  • This is part 4 of the infinite power tower
    0:00 review
    1:26 what does (cbrt(3))^(cbrt(3))^(cbrt(3))^... really converge to?
    5:40 the 3 shows up!
    6:40 the graphs of y=x^x^x... vs x=y^(1/y)
    8:05 a very similar example
    9:10 x^x^x^...=3 has no solution but x^3=3 does
    Lambert W function Intro: • Lambert W Function Int...
    *The Satisfyingly Strange Journey to the Infinite Power Tower*
    Part1: Solving x^x^3=2 vs. x^x^3=3 • they don’t teach these...
    Part2: Solving x^x^...=2 vs. x^x^...=3 • Infinite Power Tower E...
    Part3: Domain and Range of y=x^x^... • Domain and Range of th...
    Part4: Why (cbrt(3))^(cbrt(3))^... converges to 2.4 and NOT 3? • Why it doesn't converg...
    If you enjoy my videos, then you can click here to subscribe th-cam.com/users/blackpenredpe...
    Shop math t-shirts: teespring.com/stores/blackpen...
    Support: / blackpenredpen
    Follow: / blackpenredpen
    blackpenredpen,
    math for fun

ความคิดเห็น • 164

  • @141Zero
    @141Zero 4 ปีที่แล้ว +301

    The Lambert W function is a pathway to many abilities some consider to be unnatural.

    • @dihydrogenmonoxid1337
      @dihydrogenmonoxid1337 3 ปีที่แล้ว +20

      But will it save padme?

    • @juandaviolin
      @juandaviolin 3 ปีที่แล้ว +3

      ¿що ти думал? From a certain death?

    • @That_One_Guy...
      @That_One_Guy... 3 ปีที่แล้ว +1

      But can it express x as a function of y that's elementary ? 😏

    • @nol2521
      @nol2521 ปีที่แล้ว +4

      @@dihydrogenmonoxid1337 you will fall in love with the lambert w function instead of padme so that question is irrelevant

  • @andyiswonderful
    @andyiswonderful 3 ปีที่แล้ว +149

    So, I took 11 semesters of advanced math in college and grad school, and I am constantly amazed at how much I don't know when I watch your excellent videos.

    • @blackpenredpen
      @blackpenredpen  3 ปีที่แล้ว +21

      Thank you : )

    • @leif1075
      @leif1075 3 ปีที่แล้ว

      @@blackpenredpen Why didnt you tskenthe natural log of both sides at 1:26 first?

    • @leif1075
      @leif1075 3 ปีที่แล้ว

      @@blackpenredpen and the lam ert finctiom anyway? Does anyone actually understand what it means? And it soubds like youncintradict yiurself in the video later when you say cube root of 3 isna solution..Hope you can respond.

    • @ozzymandius666
      @ozzymandius666 3 ปีที่แล้ว

      @@blackpenredpen Perhaps one day show us a graph of y=W(x).

    • @shashankambone6920
      @shashankambone6920 3 ปีที่แล้ว +1

      @@ozzymandius666 just look at the graph of x=y×e^y... that's the graph of y=W(x)....

  • @juandaviolin
    @juandaviolin 3 ปีที่แล้ว +58

    For anyone lost watching comments from 3 months ago:
    This video was unlisted and its link was put in the description of another video. So, just a few people watched this part 4. Yesterday, Blackpenredpen changed the settings and now it is public. Have a great day!

    • @shreyan1362
      @shreyan1362 3 ปีที่แล้ว +1

      Thanks ,,, i was shocked

  • @balaramkrishnahanumanthu5869
    @balaramkrishnahanumanthu5869 4 ปีที่แล้ว +34

    My mind blew at 5:12 So the issue was transforming the equation to another equation does not work because their domain:ranges are different. What kind of equations can this happen with? Clearly when infinity comes into play, also whenever imaginary roots are possible. But how do you find functions with limited domains? It seems like an easy trap if you don't know this could happen.

  • @MuPrimeMath
    @MuPrimeMath 4 ปีที่แล้ว +120

    Those graphs are really cool!

  • @Prxwler
    @Prxwler 3 ปีที่แล้ว +157

    4:43 easy, k = w

  • @frozenmoon998
    @frozenmoon998 3 ปีที่แล้ว +25

    Very suspicious results, lol. If I wasn't into maths (such as being interested, obviously not super high level), I would probably assume that these things are made up. But honestly, it's super satisfactory even when you consider easy questions and discuss them through as if you were tackling a major problem. So satisfactory, as usual, bprp!

  • @leickrobinson5186
    @leickrobinson5186 3 ปีที่แล้ว +24

    That was a brilliant, beautiful explanation. Thank you!

  • @nou3227
    @nou3227 3 ปีที่แล้ว +7

    i love how thanks to you i can improve my math skills and im still in 10 grade i started learning complex numbers with you and you inspired me to think out of the box and more abstractly i hope one day i may know at least a fourth of what you know

  • @revoltoff
    @revoltoff 3 ปีที่แล้ว

    Blackpenredpen you are a true inspiration for me, taking a Calc 1 class for my BA bachelor ( Idk why they include it) I have motivation from your videos that I did not have before. I am certain that I will do everything to pass in my class, I am stuggling with some things but your story and your enthusiasm brother blackpenredpen , God will help me on the way to succes hopefully! Thank you for sharing your sweet knowledge brother !

  • @marcusdecarvalho1354
    @marcusdecarvalho1354 3 ปีที่แล้ว +1

    Unbelievable! Extraordinary! Marvelous!

  • @xandersafrunek2151
    @xandersafrunek2151 3 ปีที่แล้ว +4

    When you said "power tower," it made me really happy.

  • @ulanluhod9628
    @ulanluhod9628 3 ปีที่แล้ว +1

    HAPPY TEACHERS' DAY ❤️ thank you so much for your videos, I wan't you to know that we really appreciate you and what you are doing ☺️

  • @angelmendez-rivera351
    @angelmendez-rivera351 4 ปีที่แล้ว +3

    One can figure that 3 is a value that cannot be converged to because the function f = x |-> x^(1/x) attains a global maximum at x = e in the positive real numbers. Hence if x = 3, then 3^(1/3) < e^(1/e).

  • @martinhimstedt5130
    @martinhimstedt5130 ปีที่แล้ว

    Excellent!

  • @benisjamin6583
    @benisjamin6583 3 ปีที่แล้ว

    @blackpinredpin Looking fresh as always! Great video.

  • @omarfawaz1051
    @omarfawaz1051 3 ปีที่แล้ว

    Beautiful... Thanks🌹

  • @MK-rh4wx
    @MK-rh4wx 3 ปีที่แล้ว

    i love how you explain it

  • @magicodabola10
    @magicodabola10 4 ปีที่แล้ว

    Amazing!

  • @asharmasharma51
    @asharmasharma51 3 ปีที่แล้ว

    From India watching you nice concept loved it

  • @SuperYoonHo
    @SuperYoonHo 2 ปีที่แล้ว

    very nice!

  • @nafrost2787
    @nafrost2787 3 ปีที่แล้ว +3

    10:14 so what you're saying, is that the two graphs (and therefore the two equations) are only equivalent on certain intervals, and 3 is outside of this interval, but this bags the question, how do you find the interval in which the two equations are equivalent?

  • @rajmanitiwari5346
    @rajmanitiwari5346 3 ปีที่แล้ว +2

    I'm in class 12 cbse 2020-21 batch
    I don't know what's happening but yes it looks cool to solve your questions ❤️❤️🥰

  • @soulsilencer1864
    @soulsilencer1864 3 ปีที่แล้ว

    Hi, love your videos, can you take the integral from -2 to 2 sqrt(1-x^2) dx ?

  • @jibiteshsaha4392
    @jibiteshsaha4392 3 ปีที่แล้ว +2

    Please someone explain me how does the fixed point convergence criteria come
    How does that interval come

  • @gtziavelis
    @gtziavelis 3 ปีที่แล้ว

    Well, well, well... excellent!

  • @LShadow77
    @LShadow77 3 ปีที่แล้ว

    Hello! Can you make the video where you get the link between the Riemann zeta function and Bernoulli numbers kind of B(t) = -t*Zeta(1-t). How is it gotten? I triied to get this equotion but I couldn't - only my brain was broken! Thanks, I hope for this video will appear soon...

  • @LUCATRON-hs8cj
    @LUCATRON-hs8cj 3 ปีที่แล้ว

    Nice song at the end

  • @tomatrix7525
    @tomatrix7525 3 ปีที่แล้ว

    Wow that function is cool

  • @efulmer8675
    @efulmer8675 ปีที่แล้ว

    For the infinite power tower, I am curious why it doesn't converge at values between 0 and e^-e. I tested 0.05 up to 30 copies of 0.05 and it jumps back and forth between ~0.1 and ~0.7 getting closer towards some value between those two numbers so it seems like it would converge to some specific value. I wonder if values between 0 and e^-e exhibit some kind of bifurcation chaos where they stay finite but bounce between two values and thus diverge in that way.

  • @vaibhavm2916
    @vaibhavm2916 3 ปีที่แล้ว

    Can you pls tell me which company markers do you use.they seem pretty easy to hold 2 in a hand and switch

  • @xinpingdonohoe3978
    @xinpingdonohoe3978 2 หลายเดือนก่อน

    So I suppose the different values for W come out when you use different cube roots of 3. All these multivalued functions are countable, so it should be able to be bijected.

  • @Bobbius-il9rf
    @Bobbius-il9rf 3 ปีที่แล้ว

    Brilliant XD

  • @djvalentedochp
    @djvalentedochp 4 ปีที่แล้ว

    Nice

  • @jibiteshsaha4392
    @jibiteshsaha4392 3 ปีที่แล้ว

    I asked this in the previous video
    I want a proof for the fixed point convergence criteria

  • @fsf471
    @fsf471 3 ปีที่แล้ว +2

    Holy shit I was just thinking of this earlier did you read my mind?

  • @logicalproofs7276
    @logicalproofs7276 3 ปีที่แล้ว +1

    Regular videos
    Woooooow

  • @NekoAlosama
    @NekoAlosama 4 ปีที่แล้ว +2

    ooh

  • @willyou2199
    @willyou2199 3 ปีที่แล้ว

    f(z) = ze^z is not monotonically increasing and thus the inverse f^-1(z) = W(z) is multivalued. Quite easy. Same with sin, cos, tan except those are periodic and easy to understand.

  • @jibiteshsaha4392
    @jibiteshsaha4392 3 ปีที่แล้ว +2

    I am really trying to find the derivation of the fixed point convergence criteria
    I tried everywhere
    Didn't find anything
    Not even in lot of papers
    Plz someone help me

  • @shubhampradhan5348
    @shubhampradhan5348 3 ปีที่แล้ว

    Sir please provide the PDFs of 100 integrals, 100 derivatives, 100 series...
    Humble request👍👍

  • @meiwinspoi5080
    @meiwinspoi5080 3 ปีที่แล้ว

    cool.

  • @oxygen2623
    @oxygen2623 ปีที่แล้ว

    1:00
    Well, that escalated quickly

  • @georgeb8893
    @georgeb8893 3 ปีที่แล้ว

    Here is a related problem where cube root of 3 does seem to be the answer: suppose start with a reasonably large number, say 100. Then you start taking log base some fixed number x greater than 1. Then you notice that the more you take log base x the closer and closer it gets to 3. What was the x?

    • @shashankambone6920
      @shashankambone6920 3 ปีที่แล้ว

      So.. ln(100)/ln(x) = 3? Is that what we are trying to solve? Because that's trivial....

  • @i_saidmeow2469
    @i_saidmeow2469 3 ปีที่แล้ว

    The chomper microphone!

  • @shruggzdastr8-facedclown
    @shruggzdastr8-facedclown 2 ปีที่แล้ว

    Is there a number such that when applied to an infinite power tower it converges on pi?

  • @rateeshk8175
    @rateeshk8175 3 ปีที่แล้ว +1

    Is three (3) the only misbehaving number in these problems???

  • @peterruf1462
    @peterruf1462 3 ปีที่แล้ว

    Why does the power tower oscillate if you chose x smaller than e^-e?

  • @djttv
    @djttv 3 ปีที่แล้ว +3

    Here is a question for you:
    Given:
    A=(1/2)sqrt((1/2)(3-sqrt(5)))
    B=(1/4)(sqrt(5)-1)
    It can be shown that A=B
    Question is, given A, how do you turn it into B?

    • @blackpenredpen
      @blackpenredpen  3 ปีที่แล้ว +1

      djttv
      It’s similar to this one th-cam.com/video/afz3t8R34r4/w-d-xo.html

    • @djttv
      @djttv 3 ปีที่แล้ว +1

      @@blackpenredpen I learned something new! Thank you

  • @ordinary1017
    @ordinary1017 3 ปีที่แล้ว

    U're the best

  • @particleonazock2246
    @particleonazock2246 3 ปีที่แล้ว

    You know you're dealing with advanced math when blackpenredpen doesn't summon the fish.

  • @gudmundurjonsson4357
    @gudmundurjonsson4357 3 ปีที่แล้ว +1

    dont you also assume the the power tower of x can be written as 3 when replacing it, i.e. assuming it converges?

    • @mtaur4113
      @mtaur4113 3 ปีที่แล้ว +1

      I think that assumption is how you get the false solution. tower = x^tower = 3, and plug in 3 for tower. Well, the tower built from 3 actually diverges toward infinity.

    • @shashankambone6920
      @shashankambone6920 3 ปีที่แล้ว

      Exactly. That's exactly the problem.

  • @justinlink1616
    @justinlink1616 4 ปีที่แล้ว

    My head is going to expode.

  • @nafrost2787
    @nafrost2787 3 ปีที่แล้ว

    This guys is really addicted to the W function.

  • @Dear999
    @Dear999 3 ปีที่แล้ว

    Pendyala education and eentertainment 👍

  • @vaibhavm2916
    @vaibhavm2916 3 ปีที่แล้ว

    I just thought for a moment,why his beard was shorter than usual. But later I realized that this video was shot months before.

  • @MeOKMeO
    @MeOKMeO 3 ปีที่แล้ว

    So interesting pardon my naive,
    Never thought about X^(1/X) when X =3 that (3)^(1/3) equals to when X =~2.478 that (~2.478)^(1/~2.478), indeed wonder how many numbers between that range has two real solutions as pairs🤔, very interesting!

    • @MeOKMeO
      @MeOKMeO 3 ปีที่แล้ว

      Downloaded a curve equation generator, between 1 and e

    • @shashankambone6920
      @shashankambone6920 3 ปีที่แล้ว

      How many numbers? Infinite....

  • @beltin_time
    @beltin_time 11 หลายเดือนก่อน

    I came to same equation 3^(⅓k) = k, but then I took ln() of both sides
    ⅓k ln(3) = ln(k)
    Divide both sides by k
    ln(3)/3 = ln(k)/k
    k = 3
    Why is it wrong?

  • @swampman4204
    @swampman4204 3 ปีที่แล้ว

    Hello bprp!!!!

  • @joejavacavalier2001
    @joejavacavalier2001 3 ปีที่แล้ว

    But how would you calculate W lambert values manually?

    • @savitsios
      @savitsios 3 ปีที่แล้ว

      Same as the natural log, you basically can't
      Or with trial and error

    • @shashankambone6920
      @shashankambone6920 3 ปีที่แล้ว

      @@savitsios i mean there are many ways to approximate....

  • @omshandilya8888
    @omshandilya8888 3 ปีที่แล้ว

    2020 raise to the power 2019 - 2020 divided by 2020 square + 2021=N
    then find the sum of digits of n
    bro plz solve this?? trying from last 5 weeks

  • @saisrirajnallam
    @saisrirajnallam 3 ปีที่แล้ว +1

    Thank u maths teacher

  • @JSSTyger
    @JSSTyger 3 ปีที่แล้ว +1

    I have a question. Does x^x^x equal x^(x^x) or (x^x)^x?

    • @Silvar55x
      @Silvar55x 3 ปีที่แล้ว

      x^x^x = x^(x^x) always. You need parenthesis on (x^x)^x.

    • @JSSTyger
      @JSSTyger 3 ปีที่แล้ว

      @@Silvar55x MicroSoft Excel says 3^3^3 = 19683

    • @Silvar55x
      @Silvar55x 3 ปีที่แล้ว

      @@JSSTyger Well this video and discussion are about mathematics - not the peculiarities of spreadsheet applications. (There's probably a historical reason those programs do it that way - to not break compatibility with legacy software.)
      If you're talking about mathematics, "x^x^x" doesn't mean "input this string into Excel/programming language", but the abstract mathematical expression of two exponentiations stacked without parenthesis. Can't really write that as is in these comments.
      Furthermore, actually
      (a^b)^c
      = a^(bc)
      that is "b times c" in the exponent.

  • @basedblueboy8770
    @basedblueboy8770 3 ปีที่แล้ว

    @ 2:20 - when you have (3^(1/3))^k = k, couldn't you take the k-th root on both sides, so the k exponent disappears on the left (k/k=1), and the equation becomes 3^(1/3) = k^(1/k), therefore k=3? where is my logic flawed?

    • @basedblueboy8770
      @basedblueboy8770 3 ปีที่แล้ว

      Edit: just watched the rest of the video, so 3 can be a solution. This is technically a way to solve the problem, but if you solve this way without using W function, the other solutions are not intuitive.

  • @aryanbhargav9705
    @aryanbhargav9705 3 ปีที่แล้ว +1

    Now I am in future

  • @glendagiron9685
    @glendagiron9685 3 ปีที่แล้ว

    Need your help.
    What is the answer here?
    x^x^x^x^... = 10

  • @evanlewis2349
    @evanlewis2349 4 ปีที่แล้ว

    Can’t you just raise k to the 3rd power to get: 3^k = k^3 and solve as if it was x^y = y^x?

    • @evanlewis2349
      @evanlewis2349 4 ปีที่แล้ว

      If you do it like this, then you get 3^k = k^3 which means k = log3 of k^3 which equals 3* log3 of k and if you repeat this, you get k = 3 * log3 of 3 * log3 of 3 * log3 of... which evaluates to 1? There doesn’t seem to be another solution to k that makes the RHS true :/

    • @angelmendez-rivera351
      @angelmendez-rivera351 4 ปีที่แล้ว +1

      Evan Lewis You wouldn't use logarithm base 3, you would simply use the natural logarithm. k^3 = 3^k implies 3·log(k) = k·log(3), which implies log(k)/k = log(3)/3, which is solved by using the Lambert W map.

  • @haval00
    @haval00 3 ปีที่แล้ว +1

    How come some comments be from 1 month ago ??

    • @coc235
      @coc235 3 ปีที่แล้ว +2

      This video was available by link

    • @blackpenredpen
      @blackpenredpen  3 ปีที่แล้ว +1

      It was unlisted in my playlist

    • @haval00
      @haval00 3 ปีที่แล้ว

      @@blackpenredpen Ok thank you , great video btw

  • @lupusofaquarius7434
    @lupusofaquarius7434 4 ปีที่แล้ว +1

    Your pens surely hold infinite power!

    • @Silvar55x
      @Silvar55x 3 ปีที่แล้ว

      @Ajay singh Video was unlisted for ~3 months, but with link provided in the description of a previous video in the series. That's how some people could find it before it was published a few days ago.

  • @darshanvanjara6009
    @darshanvanjara6009 3 ปีที่แล้ว +1

    Integration of 1 /1+secx .....
    PLEASE SUGGEST SIR......😔😔😔😔😔😔😔😔☹️

    • @darshanvanjara6009
      @darshanvanjara6009 3 ปีที่แล้ว +1

      @3head individual done sir... THANKS a lot ..

    • @darshanvanjara6009
      @darshanvanjara6009 3 ปีที่แล้ว

      @3head individual where are you from sir. Japan??

  • @SoWe1
    @SoWe1 3 ปีที่แล้ว

    ok I'm stupid why does -2 = sqrt(x) not have any solutions even in the complex plane? i*4?

    • @aeropoulpe7818
      @aeropoulpe7818 3 ปีที่แล้ว

      sqrt(4*i) = 2 * sqrt(i) = 2 * ( sqrt(2)/2 + i*sqrt(2)/2 ) = sqrt(2) + i*sqrt(2)

    • @SoWe1
      @SoWe1 3 ปีที่แล้ว

      @@aeropoulpe7818 sqrt(4*i) = 2 * sqrt(i) = 2*(-1) = -2

    • @aeropoulpe7818
      @aeropoulpe7818 3 ปีที่แล้ว

      @@SoWe1 no i^2 = (-1) , sqrt(i) is different
      z = sqrt(i) means z^2 = i so there are 2 solutions : (z = sqrt(2)/2 + i*sqrt(2)/2 ) or (z = -sqrt(2)/2 - i*sqrt(2)/2 )

    • @SoWe1
      @SoWe1 3 ปีที่แล้ว

      @@aeropoulpe7818 rightrightright, yes
      but still, why does that equation not have any solutions?

    • @aeropoulpe7818
      @aeropoulpe7818 3 ปีที่แล้ว +1

      @@SoWe1 i'm not sure but i would say :
      - a square root of a complex number (not real) is always is a complex number (not real)
      - therefore sqrt(x) = -2 only have solutions in R
      - but sqrt(x) >= 0 in R so there are no solutions at all

  • @TecknoVicking
    @TecknoVicking 3 ปีที่แล้ว

    🔒

  • @lawrencebermudez
    @lawrencebermudez 4 ปีที่แล้ว +1

    e = 3

  • @DeadJDona
    @DeadJDona 3 ปีที่แล้ว +1

    6:22 how could complex numbers infinite power look?

  • @chinjunyuan1720
    @chinjunyuan1720 3 ปีที่แล้ว

    3

  • @GammaFZ
    @GammaFZ 3 ปีที่แล้ว +1

    whatislambertwfunctionpleasemakeavideoonthatthanks

  • @aryangupta904
    @aryangupta904 3 ปีที่แล้ว

    Hey man
    Cube root of 3 to power cube root of 3 Infinite times
    Let it be x
    Cubing both sides
    3power cube root of 3 power cube root if 3 Infinite times=x³
    Dividing both sides by 3
    1power cube root of 3 Infinite times=x³/3
    1=x³/3
    X³=3
    X=cube root of three
    Solved.

  • @estelle_chenxing
    @estelle_chenxing 3 ปีที่แล้ว +1

    hi

  • @gordonchan4801
    @gordonchan4801 3 ปีที่แล้ว

    henlo

  • @satteshwaribharti9524
    @satteshwaribharti9524 3 ปีที่แล้ว

    Hi.. I have a challange question for you.. 😂😂

  • @ipetmycats99
    @ipetmycats99 3 ปีที่แล้ว

    how did I get here

  • @jacobhall4655
    @jacobhall4655 3 ปีที่แล้ว

    0:27 not according to physicists

  • @wallissoncoelho7451
    @wallissoncoelho7451 3 ปีที่แล้ว

    How do you learned English?

  • @oscartroncoso2585
    @oscartroncoso2585 3 ปีที่แล้ว

    First!

  • @purim_sakamoto
    @purim_sakamoto 3 ปีที่แล้ว

    うーん むずかしかった

    • @purim_sakamoto
      @purim_sakamoto 3 ปีที่แล้ว

      3週間ぶりにようやく理解しました😀
      こりゃ学部1年終えるのに8年かかっちゃうね😭😭

  • @amiasam3354
    @amiasam3354 3 ปีที่แล้ว +1

    Who came here from bprp fast

  • @joshuahillerup4290
    @joshuahillerup4290 3 ปีที่แล้ว +5

    And this is why I cringe slightly every time you (or anyone else) goes from the square root of a value to that value to a one half power without addressing that they're slightly different.

    • @yarakharam5343
      @yarakharam5343 3 ปีที่แล้ว +1

      I dont get what you're saying, how are they different?

    • @joshuahillerup4290
      @joshuahillerup4290 3 ปีที่แล้ว

      @@yarakharam5343 x^2 and x^(1/2) are inverses of each other. The square root of x is a function that takes the principal root of x^(1/2)

    • @shashankambone6920
      @shashankambone6920 3 ปีที่แล้ว +1

      Pretty sure that the x^(1/2) is not how we represent the multivalued root of x.... i mean that x^(1/2) = sqrt(x)... same domain, same range, same function.

    • @joshuahillerup4290
      @joshuahillerup4290 3 ปีที่แล้ว

      @@shashankambone6920 not what I was taught. The radix is a function, a non-integer exponent is not

    • @shashankambone6920
      @shashankambone6920 3 ปีที่แล้ว

      @@joshuahillerup4290 maybe we have different conventions...

  • @gurkiratsingh7tha993
    @gurkiratsingh7tha993 2 ปีที่แล้ว

    Technically sqrtx=+-sqrtx

  • @gtafita6392
    @gtafita6392 3 ปีที่แล้ว

    Nice