Disc/Washer Method vs. Shell Method (rotated about different lines)

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  • Опубликовано: 21 авг 2024
  • Volume of Solid of Revolution rotated about different lines. Disc method vs. shell method for calculus 1 or AP calculus students.
    Visit my site for the file and the answer key: blackpenredpen...
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Комментарии • 430

  • @blackpenredpen
    @blackpenredpen  4 года назад +289

    Hope this helps with your calculus 1 or AP calc
    Time stamps:
    a) area of the region, both vertical and horizontal rectangles 0:06
    b) rotate about x-axis, 5:58
    c) rotate about y-axis,15:16
    d) rotate about x=5, 21:51
    e) rotate about y=3, 30:56

    • @al-quran9845
      @al-quran9845 4 года назад +1

      This is not a difficult questions...I know better then you

    • @tanOcotO
      @tanOcotO 4 года назад +19

      @@al-quran9845 No, it doesn't work that way... stop saying this that's nonsense.

    • @angelmendez-rivera351
      @angelmendez-rivera351 4 года назад +19

      Mathematician Way Don't be an asshole. This isn't about whether it's easy or not. It's a video meant to help calculus students who are struggling, it's obviously not meant for people such as yourself.

    • @chiragmantri4947
      @chiragmantri4947 4 года назад +2

      CAN U DO WITH X=3 ALSO??

    • @JB-ym4up
      @JB-ym4up 4 года назад

      Where's the polar rotation ?

  • @rockyboy5545
    @rockyboy5545 3 года назад +1175

    You sign up to a college only to learn it from RUclips. It makes sense. Thank you.

    • @raptorgod77
      @raptorgod77 2 года назад +5

      I’ll be doing the same

    • @78anurag
      @78anurag 2 года назад +8

      Wait you learn this in college isn't this a high school course?

    • @jamesarnold3286
      @jamesarnold3286 2 года назад +36

      @@78anurag this subject is generally learned at either the end of Calc 1 or beginning of Calc 2, or both, but this just depends on what calc 1 and 2 course you took. But people still take calc 1 in college, so it would make sense either way to be learning this in college

    • @78anurag
      @78anurag 2 года назад +2

      @@jamesarnold3286 I learnt this in Calc 1

    • @brucezhang4912
      @brucezhang4912 2 года назад +1

      fuck me too and im doing that 2am :)

  • @alanparker9608
    @alanparker9608 4 года назад +463

    I love how passionate he is when he’s doing maths

    • @malane8541
      @malane8541 Год назад +8

      Ik it’s making me happy how happy he is

  • @jackkaczmarski
    @jackkaczmarski 5 месяцев назад +23

    This man may have taken the GOAT throne. No shade to The OChem Tutor or Sal Khan (they're both great and have done a lot for me), but NO ONE has been able to teach me washer method until this man. Thank you Blackpenredpen.

  • @Josh-dp6iu
    @Josh-dp6iu 2 года назад +184

    This is the only person who’s even come close to being able to explain shell method in an understandable way

  • @panostriantaphillou766
    @panostriantaphillou766 4 года назад +158

    A washer is a thin plate with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a bolt or nut.
    en.wikipedia.org/wiki/Washer_(hardware)

    • @blackpenredpen
      @blackpenredpen  4 года назад +103

      Panos Triantaphillou omg, thank you! I always thought it as the washing machine washer lol.

    • @alexdemoura9972
      @alexdemoura9972 4 года назад +17

      Yes, _"Washer method"_ is not after someone's name. But we may suppose it is *not* related to _"washing machine"_ as in _"washer"_ , a person or device that washes something, and as in _"wash"_ verb, clean with water and, typically, soap or detergent.
      It is more related to _"washer"_ , a *flat ring* fixed under a nut or the head of a bolt to spread the pressure when tightened or between two joining surfaces, since we subtract a smaller disc from a bigger disc, we got a *washer disc* or flat ring. Do you gents agree?

    • @gianlucacastro5281
      @gianlucacastro5281 4 года назад +2

      @@alexdemoura9972 It makes a lot of sense, must be because of this.

    • @christianhaynes7596
      @christianhaynes7596 3 года назад +21

      I actually laughed out loud when he said washing machine, i thought he was joking lol

    • @exequieldelantar9641
      @exequieldelantar9641 3 года назад

      May I ask.. Is circular ring method and washer the same?..

  • @Theonlyway1445
    @Theonlyway1445 3 года назад +173

    If this guy didn’t exists, I would fail all of my calculus courses.

  • @maybritSortiz28
    @maybritSortiz28 Год назад +68

    I cannot express enough my gratitude for your videos! I struggled to conceptualize washers/disks and shells, but with your thorough explanations, I could tackle these questions with ease. Thank you!

  • @joabnyabuto6041
    @joabnyabuto6041 Год назад +17

    this man just taught me three weeks' worth of class in under an hour. That's crazy

    • @takeshisatou2371
      @takeshisatou2371 Месяц назад

      3 weeks? my university taught us this in less than a week and expect us to be able to understand it lol. My university's curriculum is insane. (Not gonna expose my university, but it's 1 of the top 5 universities in asia as of 2024.)

  • @philrunninger2359
    @philrunninger2359 4 года назад +65

    Great video! I love all the RUclipsrs making math more easily understood. Just a point of clarification... "Washer" refers to a fastener used in combination with a bolt and nut, not a washing machine.

    • @blackpenredpen
      @blackpenredpen  4 года назад +56

      Omg, that washer?!
      I always thought that as the washing machine washer lol

  • @ladyeillie671
    @ladyeillie671 Месяц назад +1

    For someone who has been confused between the shell and disk/washer methods, this was very helpful for comparison.

  • @hazemalsabagh7855
    @hazemalsabagh7855 Год назад +14

    I really appreciate that you dive deep into simple questions to ensure the fundamental understanding of the topic.

  • @incognito6751
    @incognito6751 3 года назад +12

    Ever since The Organic Chemistry Tutor started paywalling his videos, I've been struggling in math. Thank you for this.

    • @sihlesamukele4556
      @sihlesamukele4556 3 года назад +2

      i thought i would never find someone like him, but guess what i just found the one BLACKPENREDPEN

  • @AustinHoelscher
    @AustinHoelscher Год назад +18

    Hands down best video about this on RUclips.
    Subbed! :)

  • @silasjoao8953
    @silasjoao8953 4 года назад +31

    man i'm brazilian and my classes were suspended due to the covid-19 pandemic, your classes have helped me a lot, here we see this in calculus 2 continue with this incredible work and may god bless you

    • @panovitch
      @panovitch 4 года назад +1

      kkkkkkk br realmente ta em todo lugar

    • @rafaelb.333
      @rafaelb.333 4 года назад

      Acompanho esse canal desde que comecei a estudar matemática direito hue

    • @andrewcarvalho9158
      @andrewcarvalho9158 4 года назад

      Isso aí é cálculo 2?

    • @panovitch
      @panovitch 4 года назад

      @@andrewcarvalho9158 sim mano, calculo de volume de solidos usando integral

    • @LuizFernando23250
      @LuizFernando23250 2 года назад

      @@andrewcarvalho9158 Eu vi em cálculo 1 mesmo

  • @ld-vt9sn
    @ld-vt9sn 3 года назад +14

    I can't believe that a few years ago I watched your channel, and I had no clue what all those hieroglyphs were on the whiteboard, And now I'm watching your videos for an explanation! keep up the amazing work, I love your videos! thanks!

  • @tanOcotO
    @tanOcotO 4 года назад +44

    Yes, thank you, we skipped all of this because of the pandemic in my calc class

  • @Alex-bc3tt
    @Alex-bc3tt 2 года назад +7

    This video needs to be the first thing lectures show to their students 🤣🤣🤣Very much descriptive and straight to the point, it even helps train the mind how to visualize the solids of revolution. Keep up the good work 🙏🙏🙏

  • @sukaygisiz8052
    @sukaygisiz8052 3 года назад +5

    i've never commented on a youtube video before, but dude i was depressed at my final exam week and you made my day with your smile. thank you! keep doing it. you are amazing at your job.

  • @andrewa7952
    @andrewa7952 3 года назад +15

    A great help visualizing when online classes don't do nothing!

  • @fkncompton7124
    @fkncompton7124 4 года назад +20

    Learned this like 2 years ago and watched the whole thing anyways for a refresher lol good video

    • @Sg190th
      @Sg190th 4 года назад +3

      Haha same. I didn't get a full grasp of learning this but it was really fun. Everything in previous math used for calculus. Can't believe I thought it was generally difficult.

  • @DavGre
    @DavGre 2 года назад +3

    Thank you for using the same two functions for the different examples, I hate when some videos try to explain the different rotations but pick a bunch of different functions for each method and rotation, this makes it crystal clear to understand the fundamental concepts without having to rewatch or pause a lot.

  • @marcusmoulia639
    @marcusmoulia639 Год назад +8

    you can really see how passionate he is for teaching math through this video. great work, keep it up!!

  • @epictrooper2568
    @epictrooper2568 3 года назад +7

    You made this so easy to understand. Up until this point I did not really understand these methods at all but now I actually understand what I'm doing. Thanks!

  • @rachelkiss302
    @rachelkiss302 3 года назад +11

    God Bless his soul. He just saved me for my test tomorrow. Thank you for your service sir.

  • @maggiedriggs9642
    @maggiedriggs9642 2 года назад +4

    he somehow made me smile doing math! such a kind and clear teacher, thank you for these lessons!

  • @banthatiwisdom6783
    @banthatiwisdom6783 2 года назад +2

    Thank you for your time. If it wasn't you I would have not understood all these. *Highly appreciated from South Africa*

  • @jamerthegamer13
    @jamerthegamer13 26 дней назад

    9:30 man i never thought about them as two different
    disk methods, that’s so much easier thank you!

  • @milk6489
    @milk6489 8 месяцев назад

    bro you dont understand how much i love your explaining and the way you teach, ive never thought id give props to a tutor on youtube but you are levels beyond anyone else on youtube teaching

  • @narutofan2010san
    @narutofan2010san 3 месяца назад +1

    You are a king! You explained chapter 7.2 of the Stewart Calculus textbook in 30 mins. Thank you sir!

  • @matzacomn
    @matzacomn Год назад +1

    I love you, seriously.
    You've helped me so much through college

  • @onion-brawlstars9792
    @onion-brawlstars9792 3 года назад +1

    this video integrates everything you need to know to ace solid of revolution

  • @chasemckinley2
    @chasemckinley2 Год назад

    I'm blown away that this much visual clarity on volumes of solids of revolution came from a video without some 3D graphics computer program involved. Loved the vid/thanks for making this!

  • @collinnovak8914
    @collinnovak8914 3 года назад +4

    this man draws better than my professor at Purdue

    • @stimulus7222
      @stimulus7222 3 года назад

      Hahha. I will come back and verify this comment after next fall😎👏

  • @makke2170
    @makke2170 3 года назад +2

    This is probably one of the best, if not the best, ways to learn maths. Fantastic video!!

  • @marazali1816
    @marazali1816 2 года назад +4

    this has been a great help to actually understand the concept, i am very thankful for this video my good sir

  • @zunairarahat
    @zunairarahat Год назад

    I blanked out for 2 hours trying to learn this in class and fully understood you in less time. Thank you so much!

  • @aftabafii.
    @aftabafii. 2 года назад

    Clean explained everything without any confusion give me a lot of concept without questioning answering

  • @bobbob3659
    @bobbob3659 5 месяцев назад +1

    Mr.blackpenredpen you are the goat!!!!!!!!!!!!!!!!!!!!!!!

  • @michaela6396
    @michaela6396 2 года назад +1

    One of the best instructors I have had help me practice Calculus. Thank you for your videos

  • @biggerthaninfinity7604
    @biggerthaninfinity7604 3 года назад

    Here is one guy who makes math fun

  • @xioxy7193
    @xioxy7193 3 года назад +1

    I have a test about this today. The video recomendation was brilliant i think im ready now for it. Thank you Blackpenredpen.

  • @105-ssaiswaroopa9
    @105-ssaiswaroopa9 2 года назад +1

    I am just getting interest on the subject, just by seeing him...what ah positivity his face has!!!! Wow!!!

  • @edisonflores6486
    @edisonflores6486 Год назад

    4 years in college and this is the 1st time I understand disk washer method and shell method.

  • @gianninagarcia6842
    @gianninagarcia6842 Год назад +3

    YOU JUST SAVED ME! ALL HAIL!

  • @BalaMurugan-hk2gd
    @BalaMurugan-hk2gd 3 года назад

    You made me so much happy. I could not describe in words because my English is so poor. Thank you dude.

  • @justinhastie3851
    @justinhastie3851 3 года назад +1

    I really appreciate your enthusiasm. You breaking it down like this really shows how easy it is. Thank you so much :)

  • @simatwokirwa4500
    @simatwokirwa4500 2 года назад

    Comment on 10:44 - Washer method because the shapes do not look like wash-machine BUT because the outer shaper/graph relates to WASHER y = root-x and the inner shape y = half-x relates to BOLT that goes into washer or ring. .. .very good intuition on finding area / volumes under curves using integration. .. good job.

  • @pr0dsatya
    @pr0dsatya 2 года назад +1

    When I get my degree and start earning a salary I will certainly be donating to this channel

    • @blackpenredpen
      @blackpenredpen  2 года назад

      That’s very nice of you. Thank you. 😃

  • @aliatejeda6210
    @aliatejeda6210 6 месяцев назад

    you just saved my math grade! THANK YOU!!!

  • @geoffreybwalley6498
    @geoffreybwalley6498 2 года назад +3

    Wonderful!! I was struggling to understand the topic
    But you make it easy, I tackle questions from any angle
    Your explanation is Amazing .

  • @faroseflinch4053
    @faroseflinch4053 Год назад

    I'm having calculus test tomorrow,this help more than 2 hr lectures,wish me luck

  • @ferminenriquezamorapineda2832
    @ferminenriquezamorapineda2832 4 года назад +2

    I learned more about calculus in this video than I learned in college in one year

  • @user-gg2hl9jp3l
    @user-gg2hl9jp3l Год назад

    you have my respect sir. i now have the full understanding of shell and washer method because of you.all thanks to you sir

  • @brownwater6212
    @brownwater6212 4 года назад +10

    I'm not in Calculus yet, but I love watching your videos regardless.

  • @acoustickunal578
    @acoustickunal578 3 года назад +2

    this video helped me a lot today was my class and hardly understand anything you helped me thanks!!

  • @annierod
    @annierod 3 года назад +3

    I was able to understand the concept thanks to you 🙏

  • @gilbertley1309
    @gilbertley1309 2 года назад

    One of his best videos for sure!

  • @Nigixmitama
    @Nigixmitama Год назад

    You just saved me 25% of my whole semester, thank you!!

  • @FelixTheForgotten
    @FelixTheForgotten 2 года назад +2

    "Just like washing machine, Washer has hole in the middle." - BlackPenRedPen - 2020

  • @jonascaburnay4839
    @jonascaburnay4839 3 месяца назад

    i was having a hard time reviewing my instructor's pdf, thank you for this!~

  • @TDL0347
    @TDL0347 2 года назад +1

    I were studen 2000 years . But you are my idol

  • @Ducky_shades
    @Ducky_shades 2 года назад

    For love of calculus keep on writing my blackpen and solving my redpen

  • @thekishorkhairnar
    @thekishorkhairnar 3 года назад

    Excellent video...
    Perfect explanation...
    Love from India 🇮🇳 ❤️

  • @hillsidebilly4649
    @hillsidebilly4649 2 года назад

    This video is incredibly good.

  • @yeellee4780
    @yeellee4780 4 года назад +1

    Just in time for my AP calc exam. Thank you very much

  • @goodmen5527
    @goodmen5527 2 года назад +1

    It’s so weird to go back to the stuff that you loved so much to end up forgetting the reasoning behind it

  • @austin7843
    @austin7843 Год назад +1

    You deserve the Presidential Medal of Freedom.

  • @aiden_villa
    @aiden_villa Год назад

    loved the martini glass joke lol. also, very helpful video. wish me luck on my test tmrw!! lol

  • @ezachle
    @ezachle 3 года назад

    this is so much more clearer than what my teacher had taught me. thank you!

  • @potatoeater8014
    @potatoeater8014 3 года назад

    didnt understand disks+washers until this video, thank you bprp :OO

  • @enqiwu5307
    @enqiwu5307 Год назад

    Thank you so much for creating these content. I have been failing my Calc BC class until I watched your videos :)

  • @sethJeon
    @sethJeon 3 года назад

    this channel should be blackbluepen

  • @samuellim4956
    @samuellim4956 2 года назад

    thank you for helping me! You are better than my prof!!!!!!!!!!!!!!!!!!!!!!

  • @allaylu2802
    @allaylu2802 3 года назад

    This was a very well explained video. I was not able to do it on my own until this video.

  • @rageprod
    @rageprod 2 года назад

    If this is the hardest part of calculus, I'm golden.

  • @elias78910
    @elias78910 Год назад +2

    Thank you. It really helped me

  • @comingshoon2717
    @comingshoon2717 4 года назад +2

    Este video debería llamarse “lo que tu profesor de cálculo 2 no te enseña”... lamentable .... Gracias maestro BPRP💪

  • @nunoskid153
    @nunoskid153 11 месяцев назад

    YOURE THE BESTTTT THANK YOUUUU FINALLY SOMEBODY DID THIS RIGHT

  • @alexdarafeev809
    @alexdarafeev809 3 года назад

    Thank you for your service, good sir. You make the best videos for understanding calculus. Great teacher, you convey the info quickly and concisely enough that my attention doesn't drift lol.

  • @shemayrays7632
    @shemayrays7632 3 года назад

    Thank you, I learned a lot. Keep up the good work. Support here from the Philippines.

  • @isaiahlobert7843
    @isaiahlobert7843 3 года назад +1

    You are a life saver my man!

  • @suteguma0
    @suteguma0 8 месяцев назад +1

    bro teaches me more than my Calculus class 😭

  • @Anna-qp1fi
    @Anna-qp1fi 3 года назад

    Man, I really love this guy!

  • @leziehr
    @leziehr 2 года назад

    thank you for this, i really couldn't get it when only reading the module

  • @peterchan6082
    @peterchan6082 4 года назад +3

    Next time please show us how to find the volume of rotation/revolution about a SLANTED LINE (like y = x/2 in this case).

    • @johnny3475
      @johnny3475 4 года назад +1

      Rotate the function

    • @peterchan6082
      @peterchan6082 4 года назад

      @@johnny3475
      Right. Show us how.

    • @Apollorion
      @Apollorion 4 года назад

      How about rotating around the line y=5-2x ?
      (i.e. perpendicularly intersecting y=x/2 at (2,1) )

  • @jaredayala8295
    @jaredayala8295 3 месяца назад

    Personally, I would just use two integrals. Integrate first with respect to y. (x/2 =< y =< sqrt(x)) and then integrate with respect to x (0 =< x =< 4)

  • @rosendjavera7734
    @rosendjavera7734 3 года назад

    You are such a genius ,i didnt this topic was this simple❤🙌

  • @mrsamiam7872
    @mrsamiam7872 6 месяцев назад +1

    Math exam tomorrow thank you so much bro 🙏

  • @Ilias_LL
    @Ilias_LL 4 года назад +41

    Math is an integral part of my life,is is for yours?

    • @fabianoalexandre1720
      @fabianoalexandre1720 4 года назад +5

      This video being uploaded in my birthday is one of the best things that happened to me today, so yes.

    • @That_One_Guy...
      @That_One_Guy... 4 года назад +1

      Math am part of my life

    • @thewok5859
      @thewok5859 4 года назад +2

      math has been a great addition to my life

    • @KakashiChidori616
      @KakashiChidori616 3 года назад +1

      Yeah my life is the derivative of maths too

    • @davidbrisbane7206
      @davidbrisbane7206 3 года назад +2

      Maths is an interal part of my life and differentiates me from others.

  • @sicko_the_ew
    @sicko_the_ew 4 года назад +1

    Sorry if I misheard this, but you were talking of the "washing-up" kind of "washer" at one point. Just in case that's what you're trying to relate the method name to, here's Wikipedia on the nut, bolt, and washer, versionr, which fits the usage here better. en.wikipedia.org/wiki/Washer_(hardware)

    • @Apollorion
      @Apollorion 4 года назад

      I think this interpretation of the "washer" in 'washer method' would be well correct if the two integrals were fused into one, but not really when kept separate.

  • @kennymccormick6846
    @kennymccormick6846 3 года назад +2

    Holy shit, i think this video just saved me. Thank you!

  • @badiosogenyl4948
    @badiosogenyl4948 2 года назад

    the washer I think is disc cylindrical washer since it is a 3 dimensional figure.. great explainantion.. great help in times of online class where onliine modules are so difficult to understand

  • @s_naeemnaqvi8725
    @s_naeemnaqvi8725 3 года назад

    saved my calculus grade once again

  • @Marcox385
    @Marcox385 4 года назад +4

    I might be early for the video, but you are late... 2 months late, when this topic was presentend to me for the first time. As always, excelent video.

  • @Rafau85
    @Rafau85 4 года назад

    I love this guy.

  • @elshaddai6648
    @elshaddai6648 4 года назад

    Find the envelope of a straight line x/a +y/b=1 where the parameted a and b related by the equation a^n +b^n =c^n

  • @BankoleAyodeleMEG
    @BankoleAyodeleMEG 3 года назад

    Video so goated, enemies couldn't dislike

  • @juliadeluis1132
    @juliadeluis1132 Год назад +3

    Thank you for explaining this!!

  • @MFRSIAM
    @MFRSIAM 3 года назад

    this video fucking save my life , so many thanks man a truly lifesaver.