Applying First Principles to x² (1 of 2: Finding the Derivative)

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  • Опубліковано 17 жов 2024

КОМЕНТАРІ • 257

  • @masterternimus6684
    @masterternimus6684 5 років тому +103

    His teaching is amazing. However, what's really amazing is the fact that he can answer a person's question so well. It's actually quite easy(for me), to give good presentations/teachings, but what actually makes it difficult, is when they ask questions! It'll take me time to understand and think of the best way to actually solve the person's question, without confusing them even further. However, Mr.Woo barely hesitated before he understood, and solved the problem. Great respect for that.

  • @mitchellkleinholz2167
    @mitchellkleinholz2167 6 років тому +137

    What really got me into math was one day in my first Calculus class, my teacher who reminds me am lot of Eddie, let me go on for about 5 minutes working things out in my head as to WHY the derivative is what it is and not just "what is it" and he let me figure out it's real world application and meaning myself, and all of the sudden everything we had been learning about was REAL, not just something I was being told. And then my teacher said "I can't believe you just backward logic'd yourself into finding out what a derivative is. Well done." And everything was just so joyous.

    • @JayV688
      @JayV688 4 роки тому

      Mayuresh Bapat he found out the meaning of life

  • @davidtaylor6870
    @davidtaylor6870 6 років тому +360

    Thanks Eddie. I am a 68 yo and just refreshing my maths, with your help (because I can). When I was at school, in the 60's, my maths understanding was greatly elevated by understand the application ( to the real world) of the math being taught at the time. One application was logarithms. It was to explain the phenomena of the world around us, in one case about sound, and to calculate the compression of air when sound travels, is a log expression. It is likely that at each step, in your explanation, you would suggest where this math method would apply in the real world. The application of math, has given me great benefit, as I was fully engaged, and could see the meaning of math, and to see it being important for my future.

    • @JJJr14
      @JJJr14 4 роки тому +10

      your 69 now. nice

    • @nickturner2813
      @nickturner2813 4 роки тому +6

      @@JJJr14 Your spelling ability is crap now.

    • @farihatabassum6135
      @farihatabassum6135 4 роки тому +1

      💜🤍💜best of luck💜🤍💜

    • @wind_reader
      @wind_reader 3 роки тому +2

      That's a wonderful take on Math. I'm majoring in Mathematics and sometimes struggle to see the significance of the contents I'm taught because they seem too abstract.
      Anyway, I hooe you're doing well.

    • @anitasoni7200
      @anitasoni7200 3 роки тому +1

      Hi sir,
      I am Aditya soni from India
      I am impressed by your courage and love for maths, and I want a little bit help from you.
      I am studying maths but I don't know how can we apply it in the real world. if you will suggest something for the resources from where i can learn the application of maths, it will help me a lot,,
      Hoping for a positive response from you.

  • @DarthZackTheFirstI
    @DarthZackTheFirstI 6 років тому +435

    they (teachers) always told me its too complicated to explain dx/dy or we dont have the time for it :/ . this makes them look very bad now!

    • @JensenPlaysMC
      @JensenPlaysMC 6 років тому +16

      have you covered calculus ? or did u want to find it out early. as this litterally was what i did on my firsy lesson of differentiation

    • @scuzyprod.1611
      @scuzyprod.1611 3 роки тому +4

      they are bad

    • @nicoles_handle
      @nicoles_handle 3 роки тому +19

      to be fair, it is hard. he's an exceptionally good teacher.

    • @swordiexd
      @swordiexd 3 роки тому +11

      @@nicoles_handle it's not hard at all. This is a very common practice in Australian schools where he is at.
      Year 11 curriculum is the introduction with first principles and an explanation of how to get it
      Year 12 you should know how calculus works well enough to be able to simply apply rules.
      Trigonometric calculus as well as logarithmic calculus is not taught until Year 12 when the students should have a good knowledge of how and why calculus is what it is.

    • @nicoles_handle
      @nicoles_handle 3 роки тому +11

      @@swordiexd i was more talking about how hard it is to convey something so abstract, and how he makes it look easy. i get foundation, but his teaching is approachable.

  • @CervezaDeGaraje
    @CervezaDeGaraje 6 років тому +49

    If I had had you as my math teacher in high school or college many years ago everything would have been so much easier. Why did I never get the explanation of why the derivative is what it is, but instead only got the final result to be accepted as gospel? These series of videos is just great, as the rest of yours that I have watched. Thanks a lot for doing this!!

  • @clivep0100
    @clivep0100 5 років тому +53

    When I learnt this at my high school, the teacher was too interested in the rules and not the principles. Thus I found it very difficult to apply. I am 64 now and with this I am a lot clearer thank you

  • @yveqeshy
    @yveqeshy 3 роки тому +6

    The way he explains by giving context is so important, introducing the limits concept and giving the history of how we arrive at derivatives and then further showing how the 2 can be merged into a function is key to understating calculus in general.

  • @acuteawareness
    @acuteawareness 7 років тому +166

    I'm so happy I found this.

  • @brandonszczech6516
    @brandonszczech6516 3 роки тому +3

    Something about your teaching style/personality just makes me want to keep watching. Thanks

    • @kxriso
      @kxriso 7 місяців тому

      scaring the hoes pfp hell yeah

  • @okzoia
    @okzoia 6 років тому +9

    Eddie: you're a genius at clearly explaining difficult concepts - the best!

  • @marcellino2602
    @marcellino2602 4 роки тому +3

    You are not just telling me a real math, but also teach me that
    We can find wisdoms in everything, even in a math principle. To simply say, math is about dynamic perspective, and so life does
    Keep the great work sir

  • @markoconnell804
    @markoconnell804 3 роки тому +3

    It was at 1:34 I realized this was never covered in my Calculus class. 😔 now I got an A in the course and never understood what I was truly trying to do. But now I know! Thanks Eddie! Forever I will be thankful to you for this.

  • @lidarman2
    @lidarman2 Рік тому +1

    Enjoy how you are so patient with students and understand their perception.

  • @visaruruqi
    @visaruruqi 5 років тому +18

    You rock, I wish I had teachers like you

  • @yourhandyman
    @yourhandyman 4 роки тому +7

    If only I had a maths teacher like you when I was in secondary school. I learnt more in your you tube clip on calculus than I did at school. Keep up the brilliant work.

  • @possiblyunmatched1323
    @possiblyunmatched1323 4 роки тому +10

    I remember my teacher just said to memorise that formula and plug in the numbers. I never did that. Depending on the question, i always try use logic to solve the question and my understanding, not memorisation. I still am on of the worst people to do maths but i wont stop trying to improve myself. ANYONE can be good at maths.

    • @ktk1144
      @ktk1144 3 роки тому

      Idk if u understand the concept by now and the explanation behind the formulae learning some basic one might help in saving time for more complex problem which may lead to work out your mind more

  • @noopurprasad6875
    @noopurprasad6875 5 років тому +12

    Just couldn't resist commenting on this one. You made maths a beautiful subject. THANKS ALOT : )

  • @MuhammadUsman-cj9ff
    @MuhammadUsman-cj9ff 5 років тому +10

    i was unlucky i hadn't teacher like you .... i am literately copying you to explain maths to my students man you are amazing Thank you.

  • @neilnemes
    @neilnemes 4 роки тому +3

    As a teacher myself, I appreciate your work. I'm getting some inspirations from you on improving my channel for my students as well. Thank you Sir.

  • @benzel5659
    @benzel5659 6 років тому +1

    You simply are a great teacher by nature I believe. Just your energy & presence are conducive to learning. Thank you massively.

  • @timelesstrance3720
    @timelesstrance3720 6 років тому +3

    2:14 agree. In my calculus I just shifted numbers from a to b not having considered its origin. These videos have made me question everything, or what ever remains.

  • @leidenjun
    @leidenjun 4 роки тому +84

    "I want the tangent, not the secant" ... I'll put that in my bio now

    • @smash0614
      @smash0614 4 роки тому +2

      bet

    • @rafaels.2350
      @rafaels.2350 4 роки тому +6

      Thats's...actually deep man, you want the point where things converge

    • @farihatabassum6135
      @farihatabassum6135 4 роки тому

      Lol

    • @particleonazock2246
      @particleonazock2246 3 роки тому

      @@rafaels.2350 Yah, but divergent thinking is more valued in today's society. Man needs to know how to think. Think deeply.

    • @ankitanant6000
      @ankitanant6000 3 роки тому

      @@particleonazock2246 But I didn't understand
      Can you explain it to me

  • @adriannakalland2342
    @adriannakalland2342 3 роки тому

    Incredibly passionate and intoxicating teacher. You rock Mr Woo.

  • @arianaalioth
    @arianaalioth 2 роки тому

    These first three videos of his are the best explanation of calculus ive ever had…..ever….since 1997.

  • @anangelsdiaries
    @anangelsdiaries 2 роки тому

    I have just started Multivariable calculus after a sabbatical and needed a refresh on Calculus concepts and just chanced upon this video. Not only are the explanations crystal clear, the way he explains it (and the context) makes it so I am actually putting things together which I had never noticed before since I was literally just applying rules.

  • @miketaicee8570
    @miketaicee8570 3 роки тому +1

    dy/dx, I studied it over 20 years ago and only now do I see where it came from!! Math is more interesting when you can see it in the bigger picture. Thanks for the education!!

  • @JimmyJohanes
    @JimmyJohanes 4 роки тому

    The way eddie explains the difficult concept is mesmerizing

  • @arduinobanzi8348
    @arduinobanzi8348 6 років тому +6

    A superbly gifted teacher. Thank you

  • @user-cs1gh4pu9v
    @user-cs1gh4pu9v 4 роки тому +2

    Grateful that you post these online! These videos are helping me understand the fundementals in easier slower pace way. As I am taking a quick pace summer online Calculus course T_T, I feel like it's a mental sprint and I'm not good at sprinting, but I have to be.
    Thank you again!

  • @andrewburd730
    @andrewburd730 4 роки тому

    Note to David Taylor (below) and Eddie. 67 y/o and trying to help my son with A level pure maths. Both of us approaching desperation and then came across this video. A big like and many thanks. Some simple concepts make mathematics so much more enjoyable and achievable: Mathematics: geometry - shapes, algebra - relationships, probability - chance, calculus - change.

  • @kraftwerk974
    @kraftwerk974 4 роки тому +5

    I've always missed an introductory overview to any subject as this. Problem with maths is that you are normally given recipes (algorithms of some sort) when this is nothing to do with maths. I remember studying sets and rings after high school just to realise that maths are not kitchen recipes at all but something totally different. Great tutorial thank you.

    • @toastedsniper9248
      @toastedsniper9248 4 роки тому

      Same here, even in college I'm having problems with absolutely no explanations and just expressions and formulas being thrown at me haha. Eddie's videos do truly help.

    • @antoinecharlesdegaulle580
      @antoinecharlesdegaulle580 4 роки тому +1

      @@toastedsniper9248 Same

  • @IndraKumar-md9ut
    @IndraKumar-md9ut 6 років тому +1

    Very well explained Professor Eddie Woo. I wish I had a teacher like you in my college in India in the years late 1960s when I first learnt calculus. I am of the same age as David Taylor whose post I saw below. I had to struggle to grasp the subject. Of course now things are totally different, as India has made tremendous progress in science and technology, and in pedagogy too.

    • @ktk1144
      @ktk1144 3 роки тому

      Hello ,now 2020 in India introduction to calculus for me and in 2021 again a revision to the idea of calculus..... And me being a jee aspirant.... I got my intro to the idea of calculus from both teachers (coaching+school) in a way pretty similar to Mr. Eddy woo (but he has diff. Energy ofc)... And I think I got lucky after seeing the comments maybe lucky ones ain't watch this vid and are learning something newer

  • @MrRockus
    @MrRockus 4 роки тому

    A brilliant explanation of basic calculus. If only my head of maths teacher had taught it that way. This why his Express maths group flunked the additional maths exam 40 years ago on their first attempt. It's not what you teach but how you teach it. Will be subscribing for more as it's never too late to learn.

  • @shubhamglohia611
    @shubhamglohia611 Рік тому

    Hello sir , I'm from INDIA 🇮🇳& I teach mathematics in my rural area.I never found this concept such a way .the way of your teaching really make me feel the mathematics that I always wanted to involve in my teaching skill.finally I got som
    e topics of mathematics from videos but caption in English makes me less understand.I wish these videos were in Hindi.
    God always bless you sir & teachers like u bless us by such a teaching 🙏
    THANKS A LOT SIR 🙂

  • @experiencelife0321
    @experiencelife0321 6 років тому +32

    his face at 6:40 lol he's so excited about math

  • @raginald7mars408
    @raginald7mars408 6 років тому +3

    The Introduction of the digital calculator in the 70 s and then Computers - ruined definitely the mind forever! Even the Manager of a German Super market saw no problem, charging me 119 Euro for 10 Eggs...recently a customer was billed 4,6 Million Euro for her groceries...Money is no problem anymore, we have infinite Credit - and debility...I bought 2 Slide Rulers from the 60s - what a relief! Switch the old rusty Brain on - what a pain...

  • @originalwolf8297
    @originalwolf8297 4 роки тому +1

    This is a very good explanation. He could've added that f' is the Lagrange Notation, dy/dx is the Leibniz Notation and that Newton used dots to indicate derivatives.

  • @emmanuelbonsu7173
    @emmanuelbonsu7173 5 років тому +2

    I really like this lesson. Its just great. Wish i had the history about all maths topics i learnt at the elementary stage.

  • @queued3262
    @queued3262 3 роки тому

    this teacher deserves my subscription

  • @louCanitz
    @louCanitz Рік тому +1

    Watching calculus lectures to avoid comp-sci HW is a level of procrastination I've not reached before 😅

    • @JH-pt6ih
      @JH-pt6ih Рік тому

      Lol - but it’s MATH, it can’t be procrastination! There is a lot worse one can procrastinate with. (BTW - I’m procrastinating by watching because I have to fix my computer and don’t really want to.)

  • @sophiawisdom5579
    @sophiawisdom5579 Рік тому

    I never got to Calculus in 8th grade almost. More rules in geometry is why on a fisher screen projector😂. He’s giving a lot of detailed explanations to what’s going on. Quickly. Thank you! Eddie

  • @raicyceprine8953
    @raicyceprine8953 4 роки тому +1

    Wow, his students are also good that they could raise questions because of how knowledgeable they are that is also because of Eddie woo

  • @precious7902
    @precious7902 3 роки тому

    Hi,Eddie, @ 8:46 but how did you take it out of the equation without it being h/h = 1...but it shouldn't it be stated that provided h is not 0,meaning we simply can't know what the derivative is at the point?... But then if we consider instantaneous velocity, we know its not undefined ,hmm...confusing, is calculus just about probability and approximation?

  • @ashutoshrudra4632
    @ashutoshrudra4632 3 роки тому

    Eddie woo is the best explainer of mathematics on the youtube.

  • @SouravBesra
    @SouravBesra 3 роки тому

    for a guy who never understood maths, this guy made me love maths.

  • @tanneranderson8190
    @tanneranderson8190 4 роки тому +3

    I just sat through a 1h50m lecture on college calculus and learned just as much from woo on youtube in 40 minutes

  • @Syakuro
    @Syakuro 3 роки тому +1

    5:05 "...you divide by zero, it explodes." for some reason that made me chuckle

  • @AhhTheBonnie
    @AhhTheBonnie 4 роки тому

    Excellent Teacher!! Well done 👍
    Wish I had of known the whole idea of these ideas before. Thanks 🙏

  • @michaelmorgan6674
    @michaelmorgan6674 5 років тому

    your videos are awesome and you go into so much more detail than my prof or maybe you just explain it in a better way. Thank you.

  • @MaverickCF
    @MaverickCF 5 років тому +4

    U are amazing finally understanding what calculus means rather than memorizing a bunch of rules
    God bless u

  • @rayniac211
    @rayniac211 6 років тому +9

    I read that Newton actually didn't invent the concept of limits. Instead, he used infinitesimals in a sort of a mathematical "hack" that upset the mathematicians of the time because it involved this idea that a really really really small "infinitesimal" number times itself = 0.

    • @mikumikumiku
      @mikumikumiku 5 років тому +2

      Historically, Newton was not being well liked at his time. Sad sad genius..

  • @DBBBB
    @DBBBB 4 роки тому

    As someone who started watching your videos 6 years ago when I started uni, as a now qualified Engineer of 2 years, I am glad to see that these videos still are this damn good.
    You take the time to actually communicate your subject, and your passion for mathematics and teaching is clear.
    Just a long term viewer and fan dropping in to say "great job"! Keep it up, mate!

  • @santhoshkumarsaraf3669
    @santhoshkumarsaraf3669 4 роки тому

    I noticed a great and very good math teacher today ... 2020

  • @Pete-Prolly
    @Pete-Prolly 6 років тому

    "...because if you divide by zero it explodes..." you said it so cool, and casual lmao; that was awesome!!

  • @PlantiPal
    @PlantiPal 4 роки тому

    Excellent explanation and method/pace of explanation.

  • @sherwinsamson9490
    @sherwinsamson9490 3 роки тому +2

    I wish I have watched this 9 years ago before dropping out of engineering school. 😅😂😂😂

  • @ahnafs8930
    @ahnafs8930 4 роки тому +1

    when you substitute f(x)= x^2. Shouldnt it be (x^2 + h) - f(x^2)/h. Because if you foil (x+h)^2, you get x^2 + 2xh + h^2. Please explain with low math words, im only a 10th grader thanks

    • @priyaaa1892
      @priyaaa1892 4 роки тому +1

      Gradient aka slope will be delta y/delta x. So it will be (h+x)²-x²/(h+x-x).
      Solve it; we get
      =(h²+x²+2hx)-x²/h {x² will get cancelled.)
      =h²+2hx/h. {take h common from numerator and denominator)
      =h(h+2x)/h. {h will get cancelled}
      =h+2x
      Now the Lim h➡0
      So we will put h=0 (p.s we didn't keep the value of h as 0 earlier in denominator because that would become meaning less and would be of no use, in Eddie's word, it would explode.)
      So now when we put h=0, we get 2x=2x.
      That is our answer. So now, the slope will be 2x, I.e, for every x, f(x)=2x.
      Why? When u put those values to find out the slope, x will get cancelled out and 2 as our answer which was our original answer before.
      Hope this helps!

  • @isaacmalik3714
    @isaacmalik3714 2 роки тому

    2:42 that's the cleanest dotted line circle i've ever seen

  • @deepuonly10
    @deepuonly10 6 років тому +2

    The guy who raised the 0/0 question is going places

  • @anupammishra8079
    @anupammishra8079 5 років тому +1

    I just want to ask.. Mr. Eddie.. From where do u get those stuffs.. How do u get so clear picture of everything

    • @matousangare190
      @matousangare190 Рік тому

      You don't need to know it might be his secret....😮

  • @danielrio1967
    @danielrio1967 5 років тому +1

    Me, 5th year Engineering student. I passed the advanced Engineering math in 4th year, Now watching this!!!

  • @quentinsummers2531
    @quentinsummers2531 2 роки тому

    That jumper looks really comfy

  • @indianabc990
    @indianabc990 2 роки тому

    shaandaar jabardast zindabaad

  • @ridhiranjan785
    @ridhiranjan785 2 роки тому +1

    RESPECT FROM INDIA🌱

  • @agentdelta569
    @agentdelta569 7 років тому +44

    maybe i shouldnt have named myself agent delta... it gets weird people using your name in casual maths

  • @morganjones7428
    @morganjones7428 6 років тому

    Best maths teacher ever

  • @christianvillasenor5084
    @christianvillasenor5084 6 років тому

    What an EXELLENT professor.

  • @kureiwekmara1332
    @kureiwekmara1332 5 років тому

    Very good explanation am interested on but can you put more vedios on this in difficult situation

  • @JashXD
    @JashXD 3 роки тому

    I am 13 and this video helped me a lot!

  • @phurbasherpa7441
    @phurbasherpa7441 4 роки тому +2

    wished i saw this when i was doing my A levels back in 2013

  • @newearthlivingithaca
    @newearthlivingithaca 6 місяців тому

    Love this guy great teacher!

  • @agrimpuriya2585
    @agrimpuriya2585 5 років тому

    If h is not zero in the beginning how is it zero at the end of the solution. What you were supposed to say is that as h tends to zero this function f(x)=x^2 gets closer to the gradient function 2x.

  • @Estes7-08
    @Estes7-08 2 роки тому

    Great teacher amazing

  • @lsubandtrumpet2014
    @lsubandtrumpet2014 Рік тому

    In the usa we call year 11, 11th Grade in high school and 12th grade (seniors) is the last grade in high school before college (university)

  • @robinhooper7702
    @robinhooper7702 Рік тому

    You have answered the question of the pharos.

  • @karnabudhathoki5311
    @karnabudhathoki5311 2 роки тому

    Wish I had same type of explanation in my college days....Calculus I now guess is to do with non linear behavior of objects and phenomenon around us.

  • @mohitwankhede9372
    @mohitwankhede9372 4 роки тому

    Thank you so much sir.. your teaching is just like magic 💓

  • @satyam8605
    @satyam8605 3 роки тому +1

    I wish I had a teacher like you during my 11th class. But it's too late💔

  • @benardkiplimo3508
    @benardkiplimo3508 9 місяців тому

    We need to see the former students of this great professor. I am certain they're thriving in a mathematical careers.

  • @HenryFMora
    @HenryFMora 2 роки тому

    Calculus was my Archils’s Heel in Engineering School. Yes, we were given were rules to follow. But, I never realized The Concept.

  • @peaceloveharmony4854
    @peaceloveharmony4854 5 років тому

    I hate math, but I am watching this guy while drunk and learning what I hate most calc. I am already done with college, but ya this is big brain time.

  • @48-saniyapandkar95
    @48-saniyapandkar95 6 років тому

    I am so freaking happy I found your channel! Thank you!

  • @anesumukura7312
    @anesumukura7312 3 роки тому

    I wish I knew about you before I wrote my advanced level exams 🥲

  • @MurasakiBunny
    @MurasakiBunny 4 роки тому

    Man, Calculus in university would have been hella easier if the profs action mentioned all this, until this day, 20 years later, I never could figure out how the derivative rules were formed, it's so simple now. Granted, the prof that taught us ended up having 60% of the class fail...

  • @ParveenKumar-ws5tu
    @ParveenKumar-ws5tu 6 років тому

    Sir i m in love with ur maths concepts and the way u approchd....grt siir love u

  • @CrxmmW_7289
    @CrxmmW_7289 3 роки тому +1

    I’m a 11 year old watching college math that looks like calculus 2 and pop up in my recommended

  • @rebeccahoward9664
    @rebeccahoward9664 3 роки тому

    Dude you're amazing at explaining haha thank you very much :)

  • @johnngala2536
    @johnngala2536 7 місяців тому

    f(x) = f(x+h)-f(x)/x-h unlike f(x) = f(x+h)-f(x)/h would the 2nd function make sense.

  • @tristanmoller9498
    @tristanmoller9498 6 років тому +1

    This is incredible, I love it!

  • @robertjones811
    @robertjones811 5 років тому

    Holy bat signal, Batman! Eddie illuminated all that notation goop for me. I feel like Neo - " I know kung-fu!"

  • @johnngala2536
    @johnngala2536 7 місяців тому

    how did we derive at 2^2+2hx+h^2-x^2

  • @niallfinn7109
    @niallfinn7109 5 років тому +2

    HOW do you teach with so much noise?????

  • @TheRock-zf3jp
    @TheRock-zf3jp 3 роки тому

    Your the man . Appreciate it 💪🏾

  • @avidrationalist7281
    @avidrationalist7281 3 роки тому

    How did he get x^2 + 2hx+h^2-x^ from (x+h)^2-X^2??? Is that correct???

  • @zephbuxton165
    @zephbuxton165 3 роки тому

    his students are the luckiest maths students on the planet

  • @barbararudd8744
    @barbararudd8744 4 роки тому

    Amazing. I teach math and this is fantastic!!

  • @Crocodile_Boatspeed
    @Crocodile_Boatspeed 4 роки тому +1

    I’m in university and the only problem is that my calculus teacher is not you.
    He explains like the goal is to confuse as many kids as possible.

  • @jagoewey
    @jagoewey 2 роки тому

    Is there a Function for a spiral?

    • @carultch
      @carultch Рік тому

      Yes. In polar coordinates, the function r=theta, gives you a spiral.

  • @geteverything6750
    @geteverything6750 6 років тому +1

    Tjanks for helping me understanding calculus i am in 9 but i love calculus thanks a lot

  • @ritudeshpande4060
    @ritudeshpande4060 6 років тому

    Is the secant that we imagine necessarily parallel to the tangent? I think that, if the secant is parallel to the tangent (at any x) then the two points where the secant cuts the curve will not be f(x) and f(x+h) but two other points, one of which is a little earlier than f(x) and the second one which is a little later than f(x) on the curve of the function.

    • @wenwen1111
      @wenwen1111 6 років тому +3

      You are thinking about f(x) as a specific fixed point but it is not. It can be whatever it needs to be based on the value of x. and x+h will be a little bit further from where your initial position of x is.

    • @kallewirsch2263
      @kallewirsch2263 5 років тому +1

      In the general case: no
      But when the length of the chord gets smaller and smaller the secant approches the slope of the tangent. It was just in his sepcial case of looking at a circle, that the secant was parallel to the tangent and actually I am not happy with that example exactly for the reason you showed up: it confuses more then it is good for. He should have used just 2 points on the original function and demonstrate that the slope of this "secant" approaches the slope of the tangent as the second point gets closer and closer to the first one.
      please do your self a favour and forget the secant. It was just used as some sort of motivation of how to come up with a way to get at the tangent at one specific point. Actually calculating a derivative is much more then this.