Introduction to limits 2 | Limits | Precalculus | Khan Academy

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  • Опубліковано 29 вер 2007
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    Introduction to the intuition behind limits
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КОМЕНТАРІ • 475

  • @iseeu3862
    @iseeu3862 4 роки тому +543

    Those who are watching this after a lecture : RESPECT
    Those who are watching a day before exam: I can totally understand

    • @nathanielbeshane282
      @nathanielbeshane282 3 роки тому +15

      What about those who are watching before the lecture

    • @DrowQ
      @DrowQ 3 роки тому +7

      Me watching this and going to learn it in 2 years ._.

    • @nitinc7804
      @nitinc7804 2 роки тому +2

      @@DrowQ you are a prodigy man

    • @ahaanhalwai6739
      @ahaanhalwai6739 2 роки тому +1

      I am watching this cause I am curious about the topic of calculus

    • @saigeethaitv9832
      @saigeethaitv9832 2 роки тому +1

      You got me

  • @cheguevaraisgod
    @cheguevaraisgod 9 років тому +693

    890,000 views. The most attended first year Calc lecture to ever occur.

  • @monicataco3734
    @monicataco3734 6 років тому +570

    Nice to know I have 1.5 million buddies who also don't understand Calculus.

  • @khanacademy
    @khanacademy  16 років тому +240

    A limit is a definite number. I'll do a video soon on the rigorous definition of a limit.

    • @arjundebnath2059
      @arjundebnath2059 3 роки тому +6

      ok

    • @kakalukium3337
      @kakalukium3337 3 роки тому +3

      Ok... Noice one

    • @thestudiousguy5252
      @thestudiousguy5252 2 роки тому +1

      Woah i would have failed my school if it wasn't for you sir

    • @souvagyapaul8989
      @souvagyapaul8989 2 роки тому

      Sir.. I can't explain in words my gratefulness towards you... Wish you will be continuing to guide us like this ❤️🙏

    • @user-zx2et9lf8y
      @user-zx2et9lf8y 2 роки тому

      Wow 14 years ago.... Still helps
      You made history haha

  • @princepatel3427
    @princepatel3427 Рік тому +21

    I'm watching this video in 2023. But there's nothing surprising that this video is still useful as it's made by most honorable person. Also watching this video inspired me how small things turn into invaluably precious things by making heartly efforts in right way. The way that Sal started deliberately on his small computer with incredibly low resolution inspires millions of common people worldwide to startup new things in their lives. Special thanks to the one and only real educator -'Sal'.

  • @rmc10141991
    @rmc10141991 8 років тому +156

    this crap is a life saver, i don't learn shit in my actual class, but the combined with the text book and friends is the only way i can learn anything. And some how this actually makes it easy for me.

  • @TheCaffeinatedDrive
    @TheCaffeinatedDrive 10 років тому +221

    I'm calling holes "graps" for now on :D

  • @sugarandbones6272
    @sugarandbones6272 4 роки тому +52

    4:37
    i just imagine sal coming home after a party and it's 3am and he just thinks
    hey, let's make a calculus video.

  • @rampageblizzard
    @rampageblizzard 7 років тому +124

    for all of those whom don't get why lim f(2) is 4: My teacher always told me the limit is the number the graph is trying to reach. as you infinitely get closer to 2 on the x axis, the graph Is trying so hard to get to 4. due to the explained circumstances, the graph itself does not go through 4, however, that's what it's trying to reach.

    • @yashdave4752
      @yashdave4752 7 років тому +2

      Thanks mate for ur kind explanation!!! Now I think I can define it in my own words..

    • @chandlerdouglas98
      @chandlerdouglas98 7 років тому +5

      *who

    • @DotaApoomUs
      @DotaApoomUs 7 років тому +3

      i'm a visual learner and that helped a lot

    • @syafiqadly9428
      @syafiqadly9428 6 років тому +1

      How about when lim f(3) ??3 on the x axis?can someone expains?

    • @AryanaSreshthaReede
      @AryanaSreshthaReede 5 років тому +4

      @@syafiqadly9428 9 as there are no obstruction mentioned like x does not equal to 3, therefore x^2 = 3^2 =9...I'm fairly new to this topic but that's how far I understood

  • @sophc193
    @sophc193 9 років тому +49

    dude. thank you so much. i'm just starting calculus and was already freaking out (today was literally our first class and just review and an overview). now that i've watched this video it's calmed me down a lot; i feel ready for tomorrow's class. thank you! :)

    • @ariabeatrice6217
      @ariabeatrice6217 7 років тому +9

      Wow how industrious you are, to prepare for a class like that. I'm literally watching this bc I have midterms tomorrow and I don't know a thing.

    • @Hannahruda
      @Hannahruda 2 роки тому +3

      6 years later and students (like myself) are in your exact same spot. I can only hope it went well for you and that it will go well for me also

    • @Arthur-fs5vl
      @Arthur-fs5vl 11 місяців тому +1

      How was High School and University or College for you? It's been 8 years since this comment, I was only 10 at the time.

    • @sophc193
      @sophc193 11 місяців тому +1

      @@Arthur-fs5vl this is such a sweet comment! switched into the arts because calculus was not for me (as the comment 8 years ago implies), much happier now and making lots of art! hope it goes great for you too :-)

    • @Arthur-fs5vl
      @Arthur-fs5vl 11 місяців тому +1

      @@sophc193 Thank you very much Sophie, wish you the best in your future art projects and God bless!

  • @1073601
    @1073601 14 років тому +46

    it's crazy how you've helped millions of students, including myself
    thanks

  • @TheLorelei
    @TheLorelei 10 років тому +8

    You have the concept absolutely right. I think it is just the notation that is confusing, particularly since the notation uses an = sign. But what the notation means is as the graph approaches x=2 the y values will get closer and closer 4, but never reach it (until x=2). In other words, the limit is the number that the function is heading to as x gets closer to 2 (or whatever number we're interested in). I'm sure you've figured all this out by now, but maybe it can still be helpful to someone.

    • @mybabyalulu
      @mybabyalulu 5 років тому

      5 yrs later, very helpful to me. Thank you very much

    • @mohamad5762
      @mohamad5762 11 місяців тому

      9 years later helpful to me

  • @TheWizardVampire
    @TheWizardVampire 4 роки тому +16

    I think it's great that you keep showing students how the functions relate to the graphs instead of just showing them separately. It made limits feel a lot more intuitive to me. :)

  • @philv2529
    @philv2529 8 років тому +83

    wouldn't it have been cool in school if our blackboards used neon colored markers. It makes for a better presentation. (yes i realize that this is not with markers but a comp program)

    • @NoraSeed_1508
      @NoraSeed_1508 2 роки тому

      We have a smartboard in our class and it looks almost similar to the video when something is written on it .......but the background looks dark(darkest?) green instead of black and it doesn't look good. LOL .......Honestly i feel there is something satisfying about the creak of chalk while writing that makes it special 😅

  • @tiffaduckie333
    @tiffaduckie333 15 років тому +12

    I just want to say that Sal is an great teacher. I'm a college calc I student who is REALLY bad at math and I am pretty sure I'm going to pass my calc class thanks to this guy! (Final is tomorrow...wish me luck!)

  • @salmannizar7571
    @salmannizar7571 3 роки тому +4

    Bro, This video is one of the oldest videos we have. Its a treasure.

  • @trebelojaques458
    @trebelojaques458 2 роки тому +33

    _grap_
    Haha love your efforts and amazing explanation.
    You've definitely changed the education system for real, one of the few golden drops here. ❣️

    • @airenmehnaz
      @airenmehnaz 2 роки тому +1

      lol I was about to comment that and saw your comment🤣

  • @lizzyberg1082
    @lizzyberg1082 4 роки тому +4

    I don't know if youtube pays you or not and because some of us cannot afford to donate we can definitely watch adds! please go ahead and add at least two adds in your videos to support fundraise!! Thanks, soo much from Pakistan!!

  • @m1n3zz
    @m1n3zz 10 років тому +4

    I just want to thank you so much for your effort in helping others. I can use your videos for all my subjects and get so much more out of them than being in class or reading a textbook. I was so stressed out before discovering your channel. You are amazing!

  • @sand-attack
    @sand-attack 11 років тому +1

    It's been a good semester Professor Khan. I've come so far since watching this video an hour before my first Calculus exam. Brushing up for my final, just wanted to thank you for all the help getting me through this course.

  • @meltaizin2996
    @meltaizin2996 4 роки тому +8

    I was in first grade when he did this video. Here I am, 13 years later and its still so helpful!! thank you Sal.

  • @jaabirana
    @jaabirana 14 років тому +4

    calculus is not hard but very time consuming.....i really appreciate your videos and i rate them 5/5 without a doubt cuz they help me so much....may god bless u men...

  • @marianesanchez9464
    @marianesanchez9464 9 років тому +32

    omg a grap

  • @ogirv202
    @ogirv202 12 років тому +4

    I'm a Marine stationed in North Carolina, I'm heading back to college after my training and I needed a review of Calculus. I can say you explain this subject as consise as a college professor would, you've done a superb job and I laud you for it sir.

    • @tvsked
      @tvsked Рік тому +1

      how did college go bro?

    • @henok.l4202
      @henok.l4202 8 місяців тому +1

      @@tvsked it has been 11 years i am curious too🤣

  • @joymella123
    @joymella123 14 років тому

    Thank You Man... YOU ROCK, I have been sitting in my cal one class for over a month, and did not understand what a limit was or how to evulate one until this video... YOU Rock! If I ever hit the lotto, I'll be sure to compensate you!!!

  • @gobberpooper
    @gobberpooper 14 років тому +3

    thank you thank you thank you thank you thank you. I have ADD and although I loved how simple and easy to understand Calculus For Dummies was compared to my brother's college textbook, it's still a book and I quickly get bored and leaving. These videos are wonderful and I will be comming back for the whole series and perhaps for the physics and chemistry ones as well.

  • @FutureTillionaire
    @FutureTillionaire 14 років тому +2

    Great work! this should really help me prepare for pre-calculus, which have to take online over the summer

  • @SouthWestI10
    @SouthWestI10 12 років тому +1

    Sal, im 18 fresh outta high school and already joined the nuclear program with the united states navy. Im shippin out in oct for boot camp, then going to school to learn every thing a nuclear engineer needs to know. I plan on using your videos when im syumped. Also, i would not be suprised at all if you (salman kahn) recieves a nobel peace prize one day to come. Please, keep making the world a better place with your videos! Thank you so much.

  • @mrpee2482
    @mrpee2482 4 роки тому +1

    When this video was made I was at preschool .... But 12 years later I am still enjoying the works of Sal 🔥🔥🔥🔥🔥 Well Done

  • @tirupi
    @tirupi 14 років тому +1

    you rock, you have saved my life dude.... thanks from Buenos Aires, Argentina!

  • @oldsoul2829
    @oldsoul2829 6 років тому +1

    marvellous..now I am confident enough to take tution for highschool kids on limits

  • @32docholiday
    @32docholiday 16 років тому +3

    AweSOME man - love the drawings , hehe "a grap in the function" - Keep the limits, derivitaves coming .

  • @sonofjesus1464
    @sonofjesus1464 4 роки тому

    My precalculus course have a more complex version of the limit notation at the beginning of the course. But his have helped me quite a lot. I love math 😄

  • @MsMusic816
    @MsMusic816 11 років тому +1

    Btw great video! wish all teachers were as helpful as you!!!

  • @miken5771
    @miken5771 9 років тому +40

    Now 964,000 views. Let's push it to the 1,000,000 mark.

    • @pear201
      @pear201 8 років тому +2

      +Michael Nguyen 995,000 SO CLOSE

    • @EthanBrierleys
      @EthanBrierleys 8 років тому +6

      +Michael Nguyen we did it

    • @spooky6703
      @spooky6703 8 років тому +4

      +Michael Nguyen I honestly wish the views started reading 999,999.9 recurring.

    • @fiervainqueur7818
      @fiervainqueur7818 6 років тому +1

      PUSH IT TO THE LIMIT!
      Scarface approved

    • @tanishbajaj9517
      @tanishbajaj9517 5 років тому

      lol i am reading this now in 2018

  • @woo216
    @woo216 15 років тому

    thanks for this presentation ur explanations are always carefully thought out and make sense

  • @ahazfernando542
    @ahazfernando542 4 роки тому +1

    I really appreciate you Sir for your immense help to all our maths needs... You've also inspired me to make my own channel.. I've uploaded some more questions which could also help those looking here for help

  • @meghanareddy8267
    @meghanareddy8267 3 роки тому

    It helped me a lot..I am really grateful that I got your video or eslz I would have failed in my test.

  • @DP69264
    @DP69264 3 роки тому +2

    I learn more from these videos than I do with the videos provided for my class.

  • @djd829
    @djd829 4 роки тому

    This is why I didn't go to college. I'm a pretty good software developer, and I completely understand this concept. What I still don't get is the "why" part - the application of this. Even a few brief mentions of where this actually applies, where it is used, would be so helpful for it to click with me. I totally get the concept, no problem, but I'm just absorbing knowledge at this point, but not able to truly fully take it in yet. I'll keep watching the series and hopefully it will make more sense.

  • @snowboarder12653
    @snowboarder12653 13 років тому

    wow these videos are great! please keep them coming

  • @neomillmarcreas6535
    @neomillmarcreas6535 5 років тому +1

    Your voice was much better than the previous vid.

  • @36goldfinger
    @36goldfinger 16 років тому

    i watched this video and went for my math exam .. it really helped .. good job man.. thanxxxxxxxxxxxxxxxxx

  • @LearnMathsFree
    @LearnMathsFree 8 років тому

    Thank you for the video!

  • @wingsforfuture8147
    @wingsforfuture8147 9 місяців тому

    Thank uuu, it really helping meeeee

  • @nejcalvoblanco
    @nejcalvoblanco 9 років тому +30

    Why does he sound so happy at the beginning?? XD

    • @jounynFM
      @jounynFM 9 років тому +58

      He loves Limits dude.

    • @Hemenmyname
      @Hemenmyname 9 років тому +5

      jounynFM funniest, best timed comment on youtube :D, it's totally viable he loves limits that much :D, it's Sal after all :D

    • @discuss2130
      @discuss2130 9 років тому +1

      jounynFM Too much. Not needed to understand calculus.

  • @adrianapomatto1614
    @adrianapomatto1614 4 роки тому

    Loving these videos!

  • @MsMusic816
    @MsMusic816 11 років тому

    Omg! I wish I knew about Khanacademy a long time ago! It would of helped me out so much!! Dx

  • @laplandJJ
    @laplandJJ 14 років тому +1

    Great explanation..with a good sense of humor..thanks

  • @hiccuphadock5059
    @hiccuphadock5059 8 років тому +5

    sal is an amazing teacher

  • @sarbanisinha1425
    @sarbanisinha1425 5 років тому

    This man actually made studies a real gift for everyone

  • @Sharmakee
    @Sharmakee 13 років тому

    I am finally going back to college since math was my least favorite subject thanks to you Salman!!

  • @waterlily716
    @waterlily716 15 років тому

    i like this guy. this will be awesome for calc 2 next semester. YAY :)

  • @Goatie89
    @Goatie89 13 років тому

    mind okay up until 3min mark mind blown at 3:10 and beyond... great videos on how you explain this. I am eternally grateful

  • @chatsociety
    @chatsociety 11 років тому

    Great way to teach limits and calculus.

  • @nandnijotwani7584
    @nandnijotwani7584 7 років тому +1

    Thanks that was helpful 😃

  • @JoeVirella
    @JoeVirella 13 років тому

    Awesome explaining and funny too. Thanks dude!!!

  • @MsGrammarnazi
    @MsGrammarnazi 15 років тому

    Awesome teaching skills..
    Thanks for the video.
    Dana

  • @poshstars
    @poshstars 14 років тому

    thank you its all clear.

  • @waterlily716
    @waterlily716 15 років тому

    oh, i already took cal 1 (actually it was AP Calculus AB). limits are like the first thing. :)
    what i meant was this whole series on calculus will be useful in cal 2. i hope it covers some of that stuff, but even if it doesn't this is still really great for review.

  • @gwa1654
    @gwa1654 9 років тому +33

    Im from Brazil and Im just starting calculus. I attend civil Engeneering and i am so exited and nervous and such fritened.

    • @gwa1654
      @gwa1654 8 років тому +3

      Actually, I had to start over. So, I am attending calculus 1 again. And this time I hope I'm gonna succeed.

    • @gwa1654
      @gwa1654 8 років тому +1

      +Sergen Yurdakul good luck for you dude! We'll gonna succeed. ;-)

    • @anony00000000
      @anony00000000 8 років тому +6

      +Guilheme Wallace According to my experience. If you stick too much to the proof of the basic equations and thinking why they're that way, instead of accepting them just like that and use them for calculation. It'll be hard to pass.

    • @gwa1654
      @gwa1654 8 років тому

      Ann Schreiber yes, you're right. I also think that we should only do math the way it's supposed to do, not asking why, why, why. But I think this time I'm going better, I've just took my second test and think I was successful. ;-)

    • @gwa1654
      @gwa1654 8 років тому

      ***** sometimes I think it's like this. It's very hard to understand every details while we have a lot o things to learn and a lot of matters.

  • @haitiancreolewithluciano
    @haitiancreolewithluciano 3 роки тому +1

    *Loved the ‘grap’ joke*

  • @abhsag24
    @abhsag24 11 років тому

    hey you have inspired me to make my own educational videos :) and i have, on calculus
    thanks a ton :D

  • @RaabBlog
    @RaabBlog 10 років тому

    i started to love math again :D

  • @lode43
    @lode43 15 років тому

    Thnx bro. As always great video.

  • @apricotsnms516
    @apricotsnms516 14 років тому

    wow that was interesting thank you!

  • @lol-rw7yd
    @lol-rw7yd 5 років тому

    Great video very helpful.....

  • @SummerPig3
    @SummerPig3 13 років тому

    I love you Khan!!!

  • @jasonli1060
    @jasonli1060 8 років тому +1

    Do limits always have to be values off the y-axis? Just for verification, limits are numerical values that a function approaches but cannot equal to?

  • @myrlamorta5567
    @myrlamorta5567 2 роки тому +1

    The voice is nice and explanation is good.

  • @DiLiG3N7
    @DiLiG3N7 6 років тому +2

    Push it to the limit! This song just popped into my head lol

  • @Goats-editz17
    @Goats-editz17 14 років тому

    you are the best thank u for ur time god bless u

  • @tammisettimuralikrishna8072
    @tammisettimuralikrishna8072 5 місяців тому

    Thank you so much sir ❤

  • @ayagjian
    @ayagjian 7 років тому +31

    haha.. gap in the graph = grap

  • @TheWheatless
    @TheWheatless 13 років тому

    This is awesome.

  • @SO-dl2pv
    @SO-dl2pv 5 років тому +1

    The concept of limit is relatively simple but people find it very confusing, I will tell you why. Most of people think that functions have a single expression in other words they think that functions are only elementary functions (polynomials, trigonoemtric, exp,... Etc or combination of them). The concept of function itself is not well explained in books so people say why in the hell we have to invent the concept of limit at all if we have just to plug the number in the function and evaluate it. In short in mathematics the concept of function is more general than elementary functions. In most applications we are familiar with basic functions. I remember once when I saw a function defined as cases (multiple expressions) I thought that is not a function but mathematically it is a function.

  • @Everything619
    @Everything619 13 років тому

    wow, i love your videos and my whole family does too!

  •  12 років тому

    Well done !!!!

  • @blackpdf1239
    @blackpdf1239 9 років тому +10

    Thumbs up for those who see this videos day before the exam.

  • @oumirci
    @oumirci 13 років тому

    U r just too good at making though look easy

  • @akankshasharma7498
    @akankshasharma7498 2 роки тому

    Watching this after 14y of release, 5y after taking my first calculus class, just brushing up concepts

  • @sasukeuciha188
    @sasukeuciha188 8 років тому

    Thanks for the videos.
    Sorry,what kind of tools or software that you used to make these videos?
    Thanks.

  • @anannyosamayel1350
    @anannyosamayel1350 6 років тому

    THE GRAP THING WAS HILARIOUS!!

  • @JustThaReal-qo8dr
    @JustThaReal-qo8dr 10 місяців тому

    I think what makes it harder for people trying to do it in quiz's is because they don't exactly have all the answer choices to begin with first time watching this video never knew it was so simple

  • @myrlamorta5567
    @myrlamorta5567 2 роки тому

    Thank you so much

  • @JohnPaydar
    @JohnPaydar 16 років тому

    thx this is great

  • @kylmrtn
    @kylmrtn 14 років тому

    Thanks for the videos man. Hopefully I'll get a 4.0 in calc =)

  • @donkeywiththemoon
    @donkeywiththemoon 14 років тому

    THANK YOU!!!

  • @Michalbasavraham
    @Michalbasavraham 13 років тому

    @TeleMentoring I love Sal's videos and mission. I will be happy to transcribe out some of the videos and Email the words off to whomever. It just has to wait until after finals.

  • @quazarphazar
    @quazarphazar 14 років тому

    I watched this and realized that I already knew how limits worked and what they are XD As soon as you wrote down the example, I blurted out "4".

  • @schirantube
    @schirantube 12 років тому

    谢谢, 真好:D

  • @ryancochran3238
    @ryancochran3238 7 років тому +11

    What field uses these functions? I'm a draftsman for an engineering firm, and with all the math I use on a daily basis, I've never seen these functions used.

    • @sharkofjoy
      @sharkofjoy 5 років тому +1

      I don't know that any field uses these directly, but these are foundational to higher level maths that I do use in various types of computing.

    • @jimmysuros6302
      @jimmysuros6302 5 років тому

      Chemical engineering.

    • @sammynnamdi4803
      @sammynnamdi4803 4 роки тому

      Am also a draughtsman maybe we can just use the graphical approach and leave the analytical analysis for them lol

    • @sammynnamdi4803
      @sammynnamdi4803 4 роки тому

      Trigonometry uses limits more than calculus but its not a field

  • @YasoAMTV
    @YasoAMTV 6 років тому +3

    What happens with the f(x)=3 when x=2, is it not considered in the limit? Just for graphing purposes

  • @AnshumanGogoi7
    @AnshumanGogoi7 14 років тому

    You dnt knw he much your videos have helpd me Sal.
    I m so glad i found you on youtube....^_^

  • @Naruto0519
    @Naruto0519 13 років тому

    We have a grap! Lol. Hey, this vid really helped me. Thanks dude! Keep pumping out vids :D Thanks Salman.

  • @rainmakr9555
    @rainmakr9555 5 років тому

    sal should get a noble prize for how many students he helped.

  • @mariazupa13
    @mariazupa13 12 років тому

    Thanks!

  • @kwilcox1126
    @kwilcox1126 13 років тому

    That was amazing

  • @AvinashRanganath
    @AvinashRanganath 15 років тому

    Grap, thats an interesting concept :)

  • @shawondas1689
    @shawondas1689 8 років тому

    its of gr8 use :)