Schrodinger Equation. Get the Deepest Understanding.

• Schrodinger Equation. ...
00:00 What is a partial second-order DEQ?
00:58 Classical Mechanics vs. Quantum Mechanics
04:27 Applications
05:14 Derivation of the time-independent Schrodinger equation (1d)
17:14 Squared magnitude, probability and normalization
25:26 Wave function in classically allowed and forbidden regions
35:34 Time-independent Schrodinger equation (3d) and Hamilton operator
38:18 Time-dependent Schrodinger equation (1d and 3d)
41:18 Separation of variables and stationary states
More: en.fufaev.org/schrodinger-equ...
Books by Alexander Fufaev:
1) Equations of Physics: Solve EVERY Physics Problem
en.fufaev.org/physics-equatio...
2) Alexander Fufaev and His Never Ending Story:
en.fufaev.org/lifestory

Пікірлер: 331

  • @fufaev-alexander
    @fufaev-alexander3 жыл бұрын

    eBook: en.fufaev.org/physics-equations-book Paperback: tinyurl.com/physics-paperback Hardcover: tinyurl.com/physics-hardcover

  • @RegiJatekokMagazin

    @RegiJatekokMagazin

    9 ай бұрын

    "This function is like when you have more time to do something, you can procrastinate, so you have the initial motivation, then for some reason you cant finish, you have some other chance to do so other days, but lower peeks, but after a while you must finish when no more time left." PT. Why would someone think otherwise, if you can aim for minimum energy consumption?

  • @adambaird8352
    @adambaird83527 ай бұрын

    Sometimes it makes me question why I'm paying for a degree when I learn the most from free KZread videos anyways

  • @MS-sv1tr

    @MS-sv1tr

    7 ай бұрын

    You need the degree to get the job. College is about 2 things: Credentialing and networking. Whether or not you actually get educated it a tertiary concern.

  • @user-je7yx7mr1s

    @user-je7yx7mr1s

    7 ай бұрын

    I agree with you. System needs to be changed.

  • @JamesVestal-dz5qm

    @JamesVestal-dz5qm

    7 ай бұрын

    You pay for a degree so the experts can understand your thinking and author your curriculum.

  • @dennisestenson7820

    @dennisestenson7820

    6 ай бұрын

    Paying for the degree motivates you to learn it from KZread. Would you be watching this for fun?

  • @TJ-hs1qm

    @TJ-hs1qm

    4 ай бұрын

    @@dennisestenson7820 yes, if a degree is you main motivation for doing physics, maybe spending your valuable life time doing something else would be a better advice.

  • @4pharaoh
    @4pharaoh Жыл бұрын

    I am shocked with how clearly you have presented this information. Fantastic job.

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    Thank you very much, 4pharaoh! 🙂

  • @FuzzyFirechu
    @FuzzyFirechu2 ай бұрын

    I literally just passed my undergrad quantum mechanics course last week, why couldn't youtube recommend it to me earlier! This was so insightful and well put together, I loved it

  • @tanvirfarhan5585
    @tanvirfarhan55852 жыл бұрын

    This was...far beyond what i expected. You could have gotten away with much, much less of an effort without any pushback. Instead, we are left with this... An absolutely beautiful, visually pleasing, simple yet concise explanations which work hand in hand with the animations to bring us an intuitive, entry-level walk-through of the schrodinger's eqation I'm honestly awe struck. I can confidently say this is easily one of the best videos on quantum mechanics I have yet had the privilege to enjoy here on KZread. (and I watch nothing but science and physics docs on KZread etc) What an absolutely superb masterpiece, what an incredibly engaging tool which undoubtedly will benefit thousands and thousands of inquisitive minds. Thank you so much for being responsible for this labor of love. It truly shows your passion for your field, and hoo boy what a treat the whole video was. It is insanely rare that animations , live explanations, and facts all come together so brilliant and organicly organized in such a way that the end product comes together to create something much, much greater than each part on it's own. What an honor

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    WOW, thank you for this motivating comment!

  • @nikhilchouhan1802
    @nikhilchouhan18023 ай бұрын

    This is the best video available on KZread explaining the Schrödinger equation. PERIOD I am a student, and I don't have money right now, but if I had I would have donated whatever you demanded without any thought whatsoever. I can't let it sink in how easy you made this look. My profs explained the same thing, taking multiple lectures but weren't 1 percent close to your explanation. Thanks a lot mate, hope you do well in your life. My best wishes with you!

  • @lepidoptera9337

    @lepidoptera9337

    3 ай бұрын

    And there is either A) the SEO bot or B) the student who hasn't found the library, yet. :-)

  • @theQuantumPenguin
    @theQuantumPenguin2 жыл бұрын

    The title does not lie!. Excellent presentation. Many concepts of math and physics are connected visually and verbally. I very much appreciated the naming of all the greek symbols and the explanations of conventional use. Very well done.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you for your positive feedback! That motivates me! Feel free to join the polls I'm doing in the community tab. There you can vote for the next video topic: kzread.infocommunity If you regularly visit my channel and like my videos, I would be happy about 1 x coffee ☕ per month: kzread.infojoin

  • @p.m.rangarajan1055
    @p.m.rangarajan105511 ай бұрын

    I keep on seeing videos on derivation, explanation and application of Schrodinger's Equation. Every single video casts an understanding only to be forgotten in a while. Trust this video remains as a benchmark on S.E., as the explanation is downright fundamental. A very good video.

  • @SergeyPopach
    @SergeyPopach26 күн бұрын

    This is the best ever explanation I found so far! Great job, Aleksander!

  • @charleschidsey2831
    @charleschidsey28319 ай бұрын

    Possibly the best and certainly the clearest explanation of the Schrödinger equation I have encountered. Strong work! You earned my sub. Look forward to more posts in the future. Thanks so very much.

  • @justaracoonchillinginatoilet69
    @justaracoonchillinginatoilet697 ай бұрын

    My professor explained the TISE so poorly I came out of that lecture so confused and questioning why I decided to take theoretical physics. This video has helped clear my mind a bit. Gonna keep going over the topic to really understand it because its still a bit of a mess to me right now but your video has helped substantially. Thank you

  • @aryanbhure5
    @aryanbhure57 ай бұрын

    Amazing. I am a Engineering Physics student, and this is the most rich detailed and clear video I found so far on schrodinger .Hats off the great explanation!

  • @wentianxiang1155
    @wentianxiang11556 ай бұрын

    The best one to explain the Schrodinger equation. Thank you.

  • @hgtrad7655
    @hgtrad765511 ай бұрын

    Your explanation has increased my understanding of Schrodinger Equation and Heisenberg uncertainty. Thank you.

  • @fufaev-alexander

    @fufaev-alexander

    11 ай бұрын

    Awesome!

  • @anthonyololo4081
    @anthonyololo40818 ай бұрын

    You did a fantastic presentation here. Thank you so much.

  • @Mortgageman145
    @Mortgageman1454 ай бұрын

    Heisenberg’s uncertainty principle is h-bar over 2 not h-bar. But then again, I can’t be certain

  • @kobbyobeng9555
    @kobbyobeng9555 Жыл бұрын

    Incredible, it was so abstract to me at first but now quite simplified. I am so elated

  • @kanwaljitsingh3248
    @kanwaljitsingh32487 ай бұрын

    You deserve a nobel Prize in explaing things

  • @frankharvey1318
    @frankharvey13188 ай бұрын

    best description i've seen. great job. i'm going to _crawl_ thru all your steps.

  • @yasinhosgor4403
    @yasinhosgor44033 жыл бұрын

    Another perfect video, great effort 👍 Looking forward to see next one

  • @haniamritdas4725
    @haniamritdas47252 жыл бұрын

    Amazingly clear presentation. Many thanks!

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you, feel free to take part in the polls for the next video topics

  • @roncho
    @roncho Жыл бұрын

    Flawless explantion of such a complex topic. You are a gifted professor

  • @pong336
    @pong3363 жыл бұрын

    Thank you for this marvellous explanation of the Schrödinger Equation!

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @HHHeiko69
    @HHHeiko697 ай бұрын

    Very very good. The best video about this topic I found so far.

  • @hqs9585
    @hqs95859 ай бұрын

    Amazing video, clear, thorough and simply GREAT! Best lecture on this equation I have ever seen and I have advanced degree in the subject. Thanks.

  • @jakeadams2562
    @jakeadams25629 ай бұрын

    This is the first time I have been able to grasp what the mathematics of quantum mechanics are actually describing, thank you!

  • @differentialxp
    @differentialxp11 ай бұрын

    I'm studying engineering and even though I'm not familiar with some of the more modern physics I understood the maths very. You just basically applied all the maths from calc 1 to calc 3/4. I was even pleasently suprised to see seperation of variables used outside of our engineering contexts. Brilliant!

  • @sh0ejin
    @sh0ejin Жыл бұрын

    thanks man! You’re a gem, I shared your channel with my friends (they’re not as enthusiastic but we liked your videos a lot). While your videos aren’t all encompassing (which is a good thing IMO, as they motivate me in the right direction) they’re very clear and with them as background I get a lot of studying done. I am grateful to you bro

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    Hey Goshujin, thank you for a very motivating comment and sharing the video. It was a great pleasure for me!

  • @vodimizoc
    @vodimizoc2 жыл бұрын

    Fantastically clear and well paced. The animations are very meaningful. Much past learning fell into place during this video.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @sylvesterjonas9141
    @sylvesterjonas91412 ай бұрын

    You are such a beautiful soul and mind; it's people like you that make me doubt my own atheism. How could a careless, random world bring about something as beautiful as your mind? I've been inspired to become a better person just by your sharing of your knowledge and goodness with us.

  • @Mikey-mike
    @Mikey-mike2 жыл бұрын

    Well done. You are an excellent teacher.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Wow, thank you very much! Feel free to join the polls I'm doing in the community tab. There you can vote for the next video topic: kzread.infocommunity If you regularly visit my channel and like my videos, I would be happy about 1 x coffee ☕ per month: kzread.infojoin

  • @vesna-wc9lo
    @vesna-wc9loАй бұрын

    Excellent explanations!! Thank you very much

  • @michellehu8264
    @michellehu82649 ай бұрын

    Very good explanation of schrodinger equation mathematically

  • @rwd420
    @rwd4205 ай бұрын

    Fantastic video, thank you very much for sharing with us!

  • @spal3907
    @spal3907 Жыл бұрын

    so good seems like schrodinger himself explained with modern understanding incorporated 🥰🥰🥰

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    haha, thank you 😄

  • @hellium8
    @hellium810 ай бұрын

    Amazingly concise and logical presentation!

  • @understrings1
    @understrings19 ай бұрын

    If I could follow, so you are a good teacher. Even with very little background in math I could follow the explanation. Well done. 🥰

  • @JohnnyGuitar1
    @JohnnyGuitar13 жыл бұрын

    What an incredibly good teacher! Thank you so much. Subscribed.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @ivansossa6601
    @ivansossa6601 Жыл бұрын

    Thankyou so much. You explained this 100x better than my professor. I am so relieved that it is not as complicated as he made it seem. Legend.

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    Hey Ivan, yeah I feel you😁

  • @TeamHarrisonMachine
    @TeamHarrisonMachine Жыл бұрын

    GREAT VIDEO!!! Thank you!!

  • @marvinbergmann704
    @marvinbergmann7047 ай бұрын

    Wow thank you, finally i understand the Schrödinger equation!

  • @misham6547
    @misham65477 ай бұрын

    Thank you so much, I didn't understand this at all while in my quantum mechanics class!

  • @leonwang3072
    @leonwang30725 ай бұрын

    Best vid on Schrodinger's Equation!

  • @hydropage2855
    @hydropage2855 Жыл бұрын

    One of my favorite videos of all time

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    oh wow, thank you very much! 🌻

  • @mlbelem
    @mlbelem7 ай бұрын

    Congrats for your outstand work and easy way of explain things🎯🎯🎯

  • @ShujaWaras-nn4fw
    @ShujaWaras-nn4fw8 ай бұрын

    Thank you for making this video .

  • @memsuniverse
    @memsuniverse5 ай бұрын

    great explanation, for a long time Schrodinger Equation was a black hole for me , until I came across this video and I had a real test of it, I am very thankful to you. great work keep it up

  • @15837pawimomo
    @15837pawimomo3 ай бұрын

    Wonderful explanation

  • @user-82086
    @user-820862 ай бұрын

    Thank you very much!It helps a lot!

  • @desolation0012
    @desolation00122 жыл бұрын

    Thank so much for helping me understand this topic!

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you for the kind comment! Feel free to join the polls I'm doing in the community tab. There you can vote for the next video topic: kzread.infocommunity If you regularly visit my channel and like my videos, I would be happy about 1 x coffee ☕ per month: kzread.infojoin

  • @camelectric
    @camelectric Жыл бұрын

    This is AWESOME!

  • @arlesterchristian8805
    @arlesterchristian88057 ай бұрын

    Thanks for this great video. And all the others you have posted. Very much appreciate the amount of time it must have taken. One suggestion - if you have not produced a video on gauge symmetry/gauge invariance - didn't find one - please give a thought to doing so. It is a very difficult topic and I have not found anything as clear on the subject as this and your other videos. You would be doing a lot of us a great favor by creating such a video. Thanks in advance for considering the suggestion.

  • @kangeroosh
    @kangeroosh2 жыл бұрын

    Absolutely amazing explanation. So detailed!

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you very much!

  • @jaseemajasmin5296
    @jaseemajasmin529610 ай бұрын

    Thankyou sir❤....this is just awesome... concept is crystal clear..keep going

  • @fufaev-alexander

    @fufaev-alexander

    10 ай бұрын

    I will! Thank you very much for your positive feedback!

  • @douglas5260
    @douglas52602 жыл бұрын

    thanks man. When your channel gets discovered by the algorithm, you'll explode.

  • @t_sixtyfivex_wing8787
    @t_sixtyfivex_wing87873 жыл бұрын

    Thank you so much 💕

  • @davidrosas2277
    @davidrosas22779 ай бұрын

    So beautifully explained, so elegantly elaborated… and yet I still don’t grasp it entirely… keep posting bro!

  • @theodoroskoudounas1395
    @theodoroskoudounas13952 жыл бұрын

    Excellent presentation

  • @david203
    @david203 Жыл бұрын

    I was hoping to see the analysis include Bohmian mechanics, where the Schrödinger equation is treated as a force acting on an isolated particle in an experiment. Add only the initial position of the particle and then you know the entire trajectory of the particle throughout the experiment. The Schrödinger equation acts as a nonlocal force, meaning a force that depends on the entire geometry of the experiment. In the case of the double-slit experiment, this force would change depending on whether the distant slit is open or closed, explaining the difference in what is seen and measured in the experiment: either a band of light or a diffraction pattern. However, the particle trajectories would always be deterministic, regardless of the experimental geometry. You could measure/observe two distinct families of trajectories, depending on whether the distant slit is open or closed. This experiment has been done several times, using low-energy (also called non-demolition) measurement, and the predicted trajectories have been verified. In this way the Born Rule (the probability density interpretation of the wave function) can be derived, instead of being taken as an axiom of the Copenhagen Interpretation.

  • @shaiplatifi6998
    @shaiplatifi69989 ай бұрын

    excellent explanation of quantum mechanics!

  • @psuecondude
    @psuecondude10 ай бұрын

    Very impressive. Thank you.

  • @amanbajracharya7403
    @amanbajracharya74039 ай бұрын

    thanks...cleared so many doubts

  • @hankieu5209
    @hankieu5209 Жыл бұрын

    Thanks a lot for such an amazing video!!!!

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    Thank you, Han! #### Want more videos? #### As a channel member you have many cool benefits: ✅ Unlock ALL Physics Videos ✅ Channel Badges For Your Nickname ✅ Unique Channel Emojis ✅ Your Vote Counts 10x in Polls ✅ Immortalization in the Hall of Fame ✅ And that's not all! CLICK -> kzread.infojoin

  • @mohammedazam74
    @mohammedazam742 жыл бұрын

    The most excellent video I've found in KZread for quantum mechanics.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you! Check out my physics website: universaldenker.org :)

  • @diraceq
    @diraceq3 жыл бұрын

    thank you so much. I love the video

  • @vaishnavipal2298
    @vaishnavipal2298 Жыл бұрын

    That's like the building blocks of Schrodinger equation n Quantum Mechanics in a nutshell. Kudos to the creator, the presentation of the concepts is amazing, it's easy to grasp, absorbing and finally feels intuitive. Great work!

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    Hey Vaishnavi, thank you very much for your positive feedback! 🤩

  • @craigfowler7098
    @craigfowler70982 жыл бұрын

    Learnt more in this video than I did in quantum mechanics course

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Oh yes, I feel you! 😁 Feel free to join the polls I'm doing in the community tab. There you can vote for the next video topic: kzread.infocommunity If you regularly visit my channel and like my videos, I would be happy about 1 x coffee ☕ per month: kzread.infojoin

  • @nigelholmes1030
    @nigelholmes10303 жыл бұрын

    Thank you. Excellent work. Very clear explanations.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @epriyblas
    @epriyblas2 жыл бұрын

    T'han you very much for this straightforward, simple, intuitive and connected to reality video... i'm taking a coure following the famous David Griffith introduction to quantum mechanics... the book shows the mathematics behind theory, but it totally lacus what i've found in this video. I learnt more in 50 minuts t'han in to weeks of mathematics país.. alhora i think both are necesary... Thanks a lot for your wonderful intuitive yet seriós and exhaustive vídeos!!

  • @anirbandey6206
    @anirbandey6206 Жыл бұрын

    Yeah it was genuinely helpgul

  • @sdsa007
    @sdsa007 Жыл бұрын

    THANK YOU! I l am very grateful for how you connected the dots for me between curvature, oscillation, normalization and quantization. Very Great Teaching!

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    Thank you Steve!

  • @dilloncrace1640
    @dilloncrace16408 ай бұрын

    Absolutely amazing

  • @Thomas-cat
    @Thomas-cat3 жыл бұрын

    another great video ! thanks for creating this masterpiece ....

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @emin5124
    @emin512410 ай бұрын

    This video is awesome. The best physic video I ever watched. I was afraid that I wouldn't understand Schrödinger equations and I was thinking that it so complex and complicated. However, after watching this video, I've been officially enlightened. I am very happy to understand. Also, I'm looking forward to the 🤩Dirac equation 🤩 video. I want to understand very well the Dirac Equation. Thank you so much.

  • @casmajd2394
    @casmajd23949 ай бұрын

    Just beautiful and comprehensive.

  • @fufaev-alexander

    @fufaev-alexander

    9 ай бұрын

    Thank you! :)

  • @kwccoin3115
    @kwccoin311510 ай бұрын

    Crazily good even though I cannot say I can understand it all. Very good.

  • @NovaWarrior77
    @NovaWarrior772 жыл бұрын

    Awesome, and appreciated.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you! Feel free to join the polls I'm doing in the community tab. There you can vote for the next video topic: kzread.infocommunity If you regularly visit my channel and like my videos, I would be happy about 1 x coffee ☕ per month: kzread.infojoin

  • @rajkumarburada3799
    @rajkumarburada3799Ай бұрын

    Well explained.

  • @DennisKorolevych
    @DennisKorolevych7 күн бұрын

    This is beautiful!

  • @ChangOhKim
    @ChangOhKim3 жыл бұрын

    Thank you..! You did really good work.!

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @ahmadabhasan8998
    @ahmadabhasan89984 ай бұрын

    Thank you very much ..great vedio

  • @Mahdi.alkawaz
    @Mahdi.alkawaz3 жыл бұрын

    thank you

  • @paulstanton4604
    @paulstanton46043 жыл бұрын

    Thanks for the video. This is very helpful.

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @billmichae
    @billmichae10 ай бұрын

    Masterful presentation.

  • @fufaev-alexander

    @fufaev-alexander

    10 ай бұрын

    Thank you!!

  • @Sarrrraah
    @Sarrrraah2 жыл бұрын

    Great vid with detailed explanation....thaaaaaanks

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you Sara! Please check out my new physics website: en.universaldenker.org/ (There's not much content there yet, but I'll add new content over time).

  • @ahmdkalef2252
    @ahmdkalef22522 жыл бұрын

    Great explanation if not the best. Thank you so much and hope to see more mathematical explanation of quantum mechanics concepts. You make things looks simple and easy to understand .

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you very much! Sure, I will produce more videos! Feel free to join the polls I'm doing in the community tab. There you can vote for the next video topic: kzread.infocommunity If you regularly visit my channel and like my videos, I would be happy about 1 x coffee ☕ per month: kzread.infojoin

  • @maddyv5660
    @maddyv5660 Жыл бұрын

    Very well presented.

  • @fufaev-alexander

    @fufaev-alexander

    Жыл бұрын

    Thank you!

  • @enchiridionv01d
    @enchiridionv01d3 жыл бұрын

    Best video i have seen,Can you make a video about Dirac equation?

  • @MALAYAPH24
    @MALAYAPH244 ай бұрын

    ❤❤❤awesome lecture

  • @JM-hu3pk
    @JM-hu3pk3 жыл бұрын

    thanks!

  • @ThanhNhan_GiaSu234
    @ThanhNhan_GiaSu2347 ай бұрын

    Very helpful❤❤❤

  • @GoogleUser-ee8ro
    @GoogleUser-ee8ro7 ай бұрын

    This video is so very helpful

  • @fufaev-alexander

    @fufaev-alexander

    7 ай бұрын

    Thank you

  • @stevenzucker2251
    @stevenzucker22512 жыл бұрын

    The visual explanation of the equation helps greatly in the understanding and analysis of the equation. Highly recommended!!

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you!

  • @ronaldjorgensen6839
    @ronaldjorgensen68399 ай бұрын

    THANK YOU

  • @dantefedeli9244
    @dantefedeli92442 жыл бұрын

    EXCELLENT EXPLANATION !!!!

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you! Would be happy if you subscribe to my channel!

  • @dantefedeli9244

    @dantefedeli9244

    2 жыл бұрын

    @@fufaev-alexander I'VE ALREADY DONE!

  • @alijoueizadeh2896
    @alijoueizadeh289610 ай бұрын

    Thank you.

  • @keandak7427
    @keandak74274 ай бұрын

    thank you so much!!!

  • @sergiolucas38
    @sergiolucas382 жыл бұрын

    Great video, thanks :)

  • @fufaev-alexander

    @fufaev-alexander

    2 жыл бұрын

    Thank you very much!

  • @girishm5880
    @girishm58803 жыл бұрын

    Outstanding

  • @DanielL143
    @DanielL1438 ай бұрын

    Excellent.