Complex Numbers Part Imaginary, but Really Simple

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  • čas přidán 11. 03. 2015
  • In this BLOSSOMS lesson, Professor Gilbert Strang introduces complex numbers in his inimitably crystal clear style. The class can go from no exposure to complex numbers all the way to Euler’s famous formula and even the Mandelbrot set, all in one lesson that is likely to require two 50-minute class sessions. Complex numbers have the form x + iy with a "real part" x and an "imaginary part" y and that famous imaginary number i, where i is the unreal square root of -1. Professor Strang shows that we should not worry about i, just work with the rule i^2 = -1. Professor Strang can hardly control his excitement as he presents these results to the class. That enthusiasm is bound to transfer over to the students. The breaks between video segments challenge the students to work through examples, assuring that they have captured the essence of the previous discussion of complex numbers. The lesson sets the foundation for the students to move further in their understanding and working with complex numbers.

Komentáře • 119

  • @nostalgia.haneen9421
    @nostalgia.haneen9421 Před 6 lety +43

    thank you I really feel happy with your lessons teacher I am a Muslim girl and in my country if we loved some one we pray for him by saying " may god give you more healthy life full of happiness without sadness "

  • @IntelligentDiscussion
    @IntelligentDiscussion Před 7 lety +48

    I had to pause the video because I was so distracted at how much respect and love I have for this professor. Odd how you can tell when someone is a great human being, I know he'd never judge me for who I am, possibly except for my math skills, and even then he'd probably merely try to help me.

  • @cyberlightbeing
    @cyberlightbeing Před 8 lety +103

    This man is such a brilliant teacher! I wish I had access to his teachings 40 years ago, thank you!

    • @geethanjalibalaji5232
      @geethanjalibalaji5232 Před 6 lety

      haha

    • @michaelnahole430
      @michaelnahole430 Před 6 lety +1

      I feel the same way prof Leonard you really simplify everything. you are gods gift to math students.

    • @Anujkumar-rt6dc
      @Anujkumar-rt6dc Před 4 lety

      czcams.com/channels/nSzn6hUZk-M7juvSAK2Eqw.html
      Notes ke liye Anirudh Sir is the best.

    • @robertw2930
      @robertw2930 Před 4 lety

      indeed the best math teacher i never knew ,but youtube mit open courses is great too bad I didn;t learn thi when I was 17-22 e to the i^2 isn't that almost euhler formula>

  • @powersoffour8152
    @powersoffour8152 Před 4 lety +5

    Honestly, this man is a true inspiration - so clear and elegant with his explanations.

  • @neurolife77
    @neurolife77 Před 4 lety +1

    I was watching Prof Strang's lectures on Linear Algebra from MIT opencourseware and was puzzled with the reference to imaginary numbers. I don't have any background on them, so I decided to pause on it and try to get info about that. Imagine how happy I was to find this video sitting first on a youtube search for: "complex numbers mit opencourseware" ! I love math, but this guy makes it awsome! Great teacher, thank you!

  • @SciHeartJourney
    @SciHeartJourney Před 3 lety +1

    Thank you Professor Strang! You really changed my life. I've had so much career success following your lectures online.

  • @s9300097
    @s9300097 Před 6 lety +2

    This lecturer wrote many books I used throughout my study of mathematics. Wish he tutored me at the universities I attended. Great teacher and a huge thank you.

  • @georgesadler7830
    @georgesadler7830 Před 2 lety

    Professor Strang, thank you for another beautiful lecture on complex numbers, Euler's famous formulas and the Mandelbrot set. In science and engineering ,Euler's famous formula is king.

  • @se2702
    @se2702 Před 2 lety

    What an amazing thing to be able to have a math lesson from this brilliant - world renowned professor. Absolutely wonderful man!!

  • @madhushreebhagwat7877
    @madhushreebhagwat7877 Před 4 lety

    i think we have lot of videos in youtube also from India not only about this concept but also for many other concept. but difference is that in our country we focus more on showoff which only helps for the companies to grow and not the students, students need these type of classes and lecture which have less showoff and provide a wonderful platform to learn the required concept more than a platform to waste their data.
    thank you sir for your wonderful lecture

  • @mathsmaths3127
    @mathsmaths3127 Před 3 lety +1

    You are humble ,down to earth and a teacher of superb understanding . Thank you so much Sir for teaching us in such a wonderful way. Thankyou so much Sir

  • @damnson1356
    @damnson1356 Před 3 lety

    best teacher i could have ever had . much respect. wish you all the best and only health and blessings may come your way. Only happy times. Stay safe professor.

  • @alemayehufeyisa9008
    @alemayehufeyisa9008 Před 5 lety +6

    dear professor
    I Wish you to live long life, you are special man
    i like you so much
    thank you

  • @epakal
    @epakal Před 5 lety

    Prof. Strang, awesome as always. Best!

  • @muhammmadkashif6784
    @muhammmadkashif6784 Před 3 lety

    The GOAT 🐐 of professors.

  • @j_adam9071
    @j_adam9071 Před 3 lety +1

    Thanks very much professor your contribution to science and knowledge is 100% certified phenomenal. Thanks 🙏

  • @Matchless_gift
    @Matchless_gift Před 6 lety +1

    Sir you are God gifted teacher for us.we are lucky to have you as professor

  • @2002budokan
    @2002budokan Před 7 lety

    Gil has enchanted us again. Amazing lecture, thank you!

  • @tapologomabotho4366
    @tapologomabotho4366 Před 3 lety

    This is amazing!! I just love maths. Thanks prof. You're the best! I wish I had a prof like you back in college

  • @SAJAN_ECE
    @SAJAN_ECE Před 5 lety +2

    He is an amazing teacher!..

  • @RC-uo3ds
    @RC-uo3ds Před 4 lety

    This man is brilliant ....
    Huge respect for you Sir .....

  • @teddygraham7599
    @teddygraham7599 Před 4 lety

    Thank you professor, you have taught me so much.

  • @amramjose
    @amramjose Před 2 lety +1

    What a great lecture and professor!

  • @kaylynnl6210
    @kaylynnl6210 Před 7 lety +1

    Amazing lecture! Math is just fascinating

  • @bunny4173
    @bunny4173 Před 3 lety

    Gilbert strang is the man

  • @franrodri88
    @franrodri88 Před 5 lety +1

    You are incredible, thnak you for exist

  • @boliu5809
    @boliu5809 Před 5 lety

    teaching so clearly, wonderful

  • @hari8568
    @hari8568 Před 6 lety

    I really loved the review in between so hilarious!!!!!

  • @jake_runs_the_world
    @jake_runs_the_world Před 7 lety

    Absolutely amazing !!

  • @MathLab4u
    @MathLab4u Před 3 lety

    I of course subscribed and admire you. You r an idol. I am a math teacher. You remind me my professor when I was in university

  • @joebrinson5040
    @joebrinson5040 Před 3 lety

    My favorite teacher

  • @aryandey2429
    @aryandey2429 Před 3 lety +1

    He is awesome

  • @koyin1244
    @koyin1244 Před 6 lety

    It is really helpful for me . I drastically kind on learning with u

  • @mhlengimthembu9351
    @mhlengimthembu9351 Před 6 lety

    What a beautiful lecture.

  • @VeraPastaEthiopia
    @VeraPastaEthiopia Před 5 lety

    Real nice & to the point introduction to imaginary numbers, i wish you would say something as to why people started to bother about complex numbers, what are their applications ?? Love you Sir, Thank you!!

  • @robertclark2607
    @robertclark2607 Před 5 lety

    I love the maths you explained so well :)

  • @hathuytu
    @hathuytu Před 3 lety

    hahaha, an idea just raised in my mind owing to the lecture. Thank you so much.

  • @jimjackson4256
    @jimjackson4256 Před 2 lety

    I gotta like this man and his knowledge.

  • @RedefiningtheConcepts
    @RedefiningtheConcepts Před 4 lety

    A great Gilbert, awesome!👌

  • @sarojpanday6236
    @sarojpanday6236 Před 4 lety

    Thank you sir very much for providing outstanding intuitions

  • @asuka-ryo
    @asuka-ryo Před 3 lety

    Man, I love this guy

  • @hubertmargreiter3508
    @hubertmargreiter3508 Před 7 lety

    I like all your uploads. I wish you would continue .....

  • @piousgold5207
    @piousgold5207 Před 7 lety +1

    thank you sir for the lesson

  • @ecaterina_trofimova
    @ecaterina_trofimova Před 7 lety +3

    Thank you!!!!!!!!!!!!!!!!!!!!

  • @ahmedchajia3478
    @ahmedchajia3478 Před 6 lety +1

    god bless you professor

  • @clarkianperez6756
    @clarkianperez6756 Před 5 lety

    i wish we had this professor in the philippines

  • @rintumondal131
    @rintumondal131 Před 5 lety +2

    OK now I have no doubt about this awesome man!
    Such a great guy....

  • @tijanajovic8358
    @tijanajovic8358 Před 2 lety

    Thank you sir! I enjoyed your lecture!

  • @hedronsciences
    @hedronsciences Před 8 lety +3

    Wow, great lecture. My objective is to translate equations to real life situations.
    This way e^z can be translated as the value by which a given image can be reflected such that the mutual viewpoint is the origin (zero).
    This means that if I projects something, then it will give a reflection and to value them equal (= understanding) I have to take an equal distance to both (projection and reflection) and that means I am back to myself at and as the origin of the whole operation.
    Whatever I project it tells something about me, the zero at/of/as the origin.
    "X" is in the I (=Eye) of the beholder.

  • @nahomgirma5501
    @nahomgirma5501 Před 6 lety

    Really good lecture sir

  • @muhammadasyraf9490
    @muhammadasyraf9490 Před 7 lety +1

    great lecturer! long live math

  • @peterpalumbo3644
    @peterpalumbo3644 Před 5 lety

    You are right. This is better.

  • @sakit4829
    @sakit4829 Před 3 lety

    Thank you master wugui

  • @pahadiGirlShobha
    @pahadiGirlShobha Před 6 lety

    u r amazing
    ur vedio is very helful for meee
    its gives a complete know ledge
    u r wonder ful🌼🌼🌼🌼🌼

  • @philmccavity
    @philmccavity Před 4 lety +4

    he makes me want to buy chalk!

  • @mdtauseefibrahim323
    @mdtauseefibrahim323 Před 4 lety

    great sir.

  • @mertcavusoglu6305
    @mertcavusoglu6305 Před 4 lety +1

    ess dayıma efsanesin

  • @takeyoubackward7524
    @takeyoubackward7524 Před 7 lety

    Great sir

  • @mark_tilltill6664
    @mark_tilltill6664 Před 4 lety

    He is the Mr. Rogers of mathematics.

  • @jay-hk1wb
    @jay-hk1wb Před 6 lety

    thanks sir

  • @parthabanerjee1234
    @parthabanerjee1234 Před 5 lety

    Gill, I love the way you teach mathematics. It is so beautiful. I liked Mathematics but you have made me fall in love with it. You are a wonderful person.

  • @aa697
    @aa697 Před 11 měsíci

    Great Great Stuff

  • @ayhanamirah2183
    @ayhanamirah2183 Před 5 lety

    very very very..... good

  • @wellesleypublishers4939

    Gilbert Strang has released Indian editions of two of his popular mathematics books, in India.
    Details are at www.wellesleypublishers.com

  • @devenderreddy9608
    @devenderreddy9608 Před 8 lety

    Sir diagrams r pentastic

  • @michaelcordova1803
    @michaelcordova1803 Před 2 lety

    Excelent.

  • @user-ec3fg3zw6p
    @user-ec3fg3zw6p Před 4 lety

    Respect

  • @adanwillams3684
    @adanwillams3684 Před 7 lety +1

    Nice

  • @sountheara9307
    @sountheara9307 Před 6 lety

    Hi Sr u has exercice about Complex , I come from Cambodia

  • @pendodigy
    @pendodigy Před 6 lety +3

    Is it possible to find the answers to the exercises anywhere??

  • @andresrequenatappi6771

    fantástico

  • @justinfleagle
    @justinfleagle Před 6 lety

    What are the applications of complex and imaginary numbers?

    • @HighestRank
      @HighestRank Před 5 lety

      Licher salsa first obviously is to provide all n solutions to an ńth order algebraic equation with unknown variables.

  • @selvams7061
    @selvams7061 Před 6 lety +1

    at 7.51 Y u divide by sqrt 2

  • @ummehabiba3681
    @ummehabiba3681 Před 3 lety

    mittag-leffler expansion of sin (1/z)=?
    tell me the answer of this question

  • @zawhtunnaing3036
    @zawhtunnaing3036 Před 7 lety +1

    which number is grater than, 2+3i and 2+5i ???

    • @prospeaker323
      @prospeaker323 Před 6 lety +2

      We can't know , in fact we can't compare complex numbers because the value of i is unkown

    • @seleccionPersonal1
      @seleccionPersonal1 Před 6 lety

      The concepts "greater than", "lower than" only exist if the kind of number are ordered. Complex numbers have not order. You can argue that distance to origin ( in polar representation ), could induce a concept of order, but this idea is not correct: 1.- all point in any circle centered in (0,0) are the same 2.- In fact you were using module of the vector ( actually R+ numbers )

  • @robertw2930
    @robertw2930 Před 4 lety

    i is my favourite number ,but it hard i don't pretend to know trig much though i used to know where i was on the unit circle

  • @erwinmeza2826
    @erwinmeza2826 Před 5 lety

    Strang well...

  • @SufiRepublic
    @SufiRepublic Před 5 lety +1

    sadly u do not have playlists !

  • @robertw2930
    @robertw2930 Před 4 lety

    my head hurts now derrivates i know 1st and 2nd once get to third i'm lost e tto the ix^2 ? this is way above my paygrade

  • @afuadebra2498
    @afuadebra2498 Před 6 lety +1

    Where from the square root of two? Please help

    • @Gabeee
      @Gabeee Před 5 lety +1

      The ~distance of the complex number is sqrt(a^2+b^2) Z = a+bi, thus normalizing the 1+i complex number results in a distance of sqrt(2) and we normalize a vector by dividing its' components by the length, now altough complex numbers are not vectors, but they work the same way in this case, resulting 1/sqrt(2) * (1+i), if you take the length of that (by a^2+b^2 = Z(Z bar) ) it's 1

    • @HighestRank
      @HighestRank Před 5 lety

      At 8:50 it is the denominator in practice example #1 contrived simply for an exercise called ‘Activity 1’.

  • @ricchburglar
    @ricchburglar Před 6 lety

    wow x squared minus 5x plus 4 equals 0 huh. Things are getting real in here.
    GREAT CLASS BY THE WAY👍🏾👍🏾👍🏾

  • @SimonClc
    @SimonClc Před 5 lety

    I don't understand, when the addition Z + Zbar is performed, we get Z + Zbar = 2.(1/sqr(2)) = sqr(2). Why is that equality true? I don't understand why it's not just (2/sqr(2)).

    • @eleniriga5513
      @eleniriga5513 Před 5 lety

      In order to simplify it, 2/sqr2= sqr2×2/sqr2×sqr2= sqr2

    • @eleniriga5513
      @eleniriga5513 Před 5 lety

      It's the same thing basically

    • @SimonClc
      @SimonClc Před 5 lety

      @@eleniriga5513 yes, sqr(2)xsqr(2) is two, I guess when you put it like that it's fairly obvious! Thanks for your answer, it's interesting to practice this sort of basic flexibility in the way I perceive numbers

  • @ivornworrell
    @ivornworrell Před 4 lety

    *Nice video professor, but I must disagree with you @ **05:00** that Gauss is the greatest mathematician of all times:Have you considered The great Sir Doctor Albert Einstein, professor, and what of The Theorems of Pappus, The great Greek scholars such as Heron of Alexandria & Pythagoras etc.?Respectfully, learned professor.*

  • @sucikman
    @sucikman Před 7 lety

    why i times i gives you 1 not i squared???

  • @operazionetrasparenza5297

    T H A N K Y O U !!

  • @MrBeen992
    @MrBeen992 Před 4 lety +1

    Actually, the solution to x^2 + 1 = 0 is +i or -i.

    • @MrBeen992
      @MrBeen992 Před 4 lety

      ok, he added the negative solution a minute later...

  • @seoexperimentations6933

    So what is Z^2?!? I got i

  • @robertw2930
    @robertw2930 Před 4 lety

    :. i thought meant therefore in math

    • @robertw2930
      @robertw2930 Před 4 lety

      no mAYBE DIDDFERENT IM THINK LOGIC NOT THE ...(ELIPSES?)

  • @wildenthusiasm
    @wildenthusiasm Před 3 lety +1

    Iota

  • @annehinrichs22
    @annehinrichs22 Před 6 lety +1

    They should name a country after z and z bar

  • @Chandinishetty2682
    @Chandinishetty2682 Před 3 lety

    So dark chalk

  • @veneshahenry8853
    @veneshahenry8853 Před 6 lety

    Give some more number

    • @HighestRank
      @HighestRank Před 5 lety

      venesha henry which, imaginary&complex or real?

  • @google6730
    @google6730 Před 5 lety

    Not realy simple :(

  • @ChechoColombia1
    @ChechoColombia1 Před 4 lety +1

    at 7.51 Y u divide by sqrt 2

    • @marciomarquesdarocha211
      @marciomarquesdarocha211 Před 4 lety +1

      Observe z is a vector that measure 1 unity and 45 degrees respect real axes.
      Therefore, Re(z) = 1cos45° = 1/sqrt(2), and Im (z) = 1sin45° = 1/sqrt(2).
      Sorry my bad english.

    • @ChechoColombia1
      @ChechoColombia1 Před 4 lety

      @@marciomarquesdarocha211 thank you, for real