Power Series & Intervals of Convergence

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  • เผยแพร่เมื่อ 28 ก.ย. 2024
  • Power series are series of the form c_n (x-a)^n where the c_n is a sequence and x is thought of as a variable. Whether it converges or diverges depends on the x. By applying the Ratio Test, we decide the interval upon which the Power Series converges, as well as the "ratio of convergence" and the "center" of the power series. The results turn out very analogous to Geometric Series.
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ความคิดเห็น • 74

  • @alkankondo89
    @alkankondo89 5 ปีที่แล้ว +50

    SUCH a clear explanation and excellent examples! What a great teacher!!

  • @dianeenyi2849
    @dianeenyi2849 5 หลายเดือนก่อน +3

    Wow, i was struggling to grasp this in class but this made it so clear. Thank you

  • @danielwright2893
    @danielwright2893 3 ปีที่แล้ว +5

    I love the video, I couldn’t understand this Power Series and watching this video made amazing clear.

    • @DrTrefor
      @DrTrefor  3 ปีที่แล้ว +1

      Glad it helped!

  • @AD-wg8ik
    @AD-wg8ik 2 หลายเดือนก่อน

    Earned a sub, your Calc II content is the best I've seen on this platform.

  • @ARecklessNinja
    @ARecklessNinja 4 ปีที่แล้ว +52

    it's 3 am, I have my exam at 8am and you might've just saved me... Thank you so much!!! Great explanations and clearly shown writings for each step. The work you do to get to each step takes a little bit to understand but not too bad at all!

    • @中文中国-t4u
      @中文中国-t4u ปีที่แล้ว +6

      did u pass ??

    • @evrenunal3644
      @evrenunal3644 ปีที่แล้ว +9

      @@中文中国-t4u been 3 years bro

    • @MemesMania.
      @MemesMania. 9 หลายเดือนก่อน +1

      ​@@evrenunal3644still stands

    • @siddhirajput16
      @siddhirajput16 7 หลายเดือนก่อน +2

      How was your exam?

    • @Salamanca-joro
      @Salamanca-joro 5 หลายเดือนก่อน +1

      ​@@evrenunal3644 we still wanna know 😂

  • @michaelmurdoch
    @michaelmurdoch 6 หลายเดือนก่อน

    Loving your calc II vids! I have a question though, if we run into an interval where R=infinity and we converge for all x, what about if x= infinity? Would that change the ratio depending on how you would then solve the limit?

  • @LunaSmith-i4u
    @LunaSmith-i4u 6 หลายเดือนก่อน

    YOU ACTUALLY ATE THIS UP THANK YOU SO MUCH WOW

  • @greenpen4145
    @greenpen4145 5 ปีที่แล้ว

    Yo I'm pretty sure you lectured my math 122 class like a month or something ago, if this was actually you I loved your lecture, if this isnt I loved you video regardless👌

  • @vijayvarma5501
    @vijayvarma5501 3 หลายเดือนก่อน

    Sir at 5:52 you say for x=1 it coverge by A.S.T
    But A.S.T is summation [ (-1)^n-1*bn ] so we check bn value for convergence
    But in the example summation [(-1)^n /n] not (-1)^n-1 then how are we using it sir

  • @matthewmak6195
    @matthewmak6195 2 ปีที่แล้ว +1

    you helped me so much. thanks😀

  • @arisoda
    @arisoda 3 ปีที่แล้ว

    why does my textbook say that you don't need to take (x-a)^n into account when using ratio test? Wouldn't these also work? It says you just need to do the ratio test of C_n

  • @modernphysics7474
    @modernphysics7474 2 ปีที่แล้ว

    Amazing explanation 👍👏 ....

  • @jaygondaliya6245
    @jaygondaliya6245 3 ปีที่แล้ว

    I am a JEE apsirant and i really wanted to know something more about interval of convergence

  • @ebimath5601
    @ebimath5601 2 ปีที่แล้ว

    Hi
    I have a question about "Convergence of a Power Series"
    Can you help me solve that?

  • @user-zj9pq5xc7x
    @user-zj9pq5xc7x ปีที่แล้ว

    amazinggg explanation. thank youuuu so much

  • @dr.winner2516
    @dr.winner2516 5 ปีที่แล้ว

    At 9:07 , the radius of convergence R can only be 0 or 1 right? As we are using ratio test?

    • @dr.winner2516
      @dr.winner2516 5 ปีที่แล้ว

      @@DrTrefor oh right, my bad

  • @thisukainol
    @thisukainol ปีที่แล้ว

    thanks a lot mannn

  • @nagabrahmeswarpusapati6930
    @nagabrahmeswarpusapati6930 12 วันที่ผ่านมา +1

    the graph is vague but ok

  • @hoibidon8896
    @hoibidon8896 4 ปีที่แล้ว

    Thanks!!!!!!

  • @aspiredifferent8085
    @aspiredifferent8085 2 ปีที่แล้ว +1

    200 SAAL JIYO AAP SIR JI

  • @princesspasquin4158
    @princesspasquin4158 11 หลายเดือนก่อน

    Useless

  • @fea6378
    @fea6378 3 ปีที่แล้ว +26

    Videos like these make me cry. Just so thankful how God has gifted you so much and you still care to share your gifts with others. Thank you.

  • @hertube02
    @hertube02 3 ปีที่แล้ว +7

    Haven't seen better explanation than this! thanks

  • @dr.winner2516
    @dr.winner2516 5 ปีที่แล้ว +4

    At 8:39 , x = 2 turned into x = 0, I don't understand

  • @shahirkazi8766
    @shahirkazi8766 3 ปีที่แล้ว +6

    Your videos are amazing Dr. Bazett. I really love your enthusiasm as you speak, and I believe that enthusiasm permeates into the mind of the viewer as well.

    • @DrTrefor
      @DrTrefor  3 ปีที่แล้ว +1

      Thank you!!

  • @ethanlane9873
    @ethanlane9873 2 ปีที่แล้ว +5

    One of the best math explanations I’ve ever heard

  • @monatoshbarman11
    @monatoshbarman11 2 ปีที่แล้ว +4

    Thank you Dr. Bazett. Just learnt/understood what these terms are..beautifully explained.. 🌻

  • @TrendCast314
    @TrendCast314 3 ปีที่แล้ว +3

    Thank you teacher

  • @Asteriascience
    @Asteriascience 4 หลายเดือนก่อน +1

    God bless best explanation on yt

  • @shaveenh.husien
    @shaveenh.husien 2 ปีที่แล้ว +1

    I don’t understand about n/n+1 ?!

  • @hiripitiyapavara3186
    @hiripitiyapavara3186 2 ปีที่แล้ว +2

    Just a clear explanation. Thank You, sir!

  • @urgjendevetak3605
    @urgjendevetak3605 ปีที่แล้ว +1

    Amazing video ! I wanted to know whether this is useful for determining the radius of convergence of the Taylor series, for example for ln(1+x) ; should we analyse the remainder function or the radius of convergence or both ?

  • @vijaysinghchauhan7079
    @vijaysinghchauhan7079 3 ปีที่แล้ว +1

    What if I have the following power series : (x-a)^cn where c is some constant or (x-a)^n^2 how to do these?

  • @sakethsreeni
    @sakethsreeni 2 ปีที่แล้ว +1

    Thanksss a lottttt sir....You're explanation is better than my prof...

  • @soniasu2744
    @soniasu2744 2 ปีที่แล้ว +1

    bro you are like jesus christ of calculus you saved me nglllll

  • @nitra01
    @nitra01 5 หลายเดือนก่อน

    8:40 editor got confused or something that's supposed to be "Series diverges unless x=2. SO R=0"

  • @jtcapperella3938
    @jtcapperella3938 5 หลายเดือนก่อน

    Great video. Small mistake at 8:40 you say diverges unless x=0 when it should be x=2.

  • @holyspirit380
    @holyspirit380 2 ปีที่แล้ว +1

    What the fffffffffunctiona , love it

  • @Salamanca-joro
    @Salamanca-joro 5 หลายเดือนก่อน +1

    I think for the first example i is [ -1 , -3 ] not [1 , 3]

    • @vijayvarma5501
      @vijayvarma5501 3 หลายเดือนก่อน

      No it is correct center =2 so [1,3] watch previous video for clearity

    • @Salamanca-joro
      @Salamanca-joro 3 หลายเดือนก่อน

      @@vijayvarma5501 i had an exam at the I commented and I passed the exam so I don't remember what was this about and I will never watch one of these series videos again ever🤣🤣

  • @LateNightRituals
    @LateNightRituals 3 ปีที่แล้ว +1

    Legend

  • @yuvrajjindal4595
    @yuvrajjindal4595 2 ปีที่แล้ว +1

    great explanation

  • @lordfarquaadreal9156
    @lordfarquaadreal9156 2 ปีที่แล้ว +5

    I really wish my teacher took the time to explan things like you do here. I assume you already know how much help you are to kids like me in college and I just gotta say I love you Dr.Trefor, please never stop making content like this!

  • @adithyan5249
    @adithyan5249 3 ปีที่แล้ว +1

    Good work

  • @monicaswartz7556
    @monicaswartz7556 4 ปีที่แล้ว +1

    Are there any restraits on c_n? Does every number in the series have to be a real constant for this to be considered a power series?

    • @DrTrefor
      @DrTrefor  4 ปีที่แล้ว +1

      While the focus in my calculus courses is indeed that c_n is a real number, the same concept certainly works for other types of coefficients, most prominently the c_n being complex numbers.

  • @yehuawang7553
    @yehuawang7553 ปีที่แล้ว +1

    he makes this topic so easy I almost forgot how much I struggled in class

    • @yehuawang7553
      @yehuawang7553 ปีที่แล้ว

      He loved my comment! I love you too sir!!!

  • @fernanmontevista204
    @fernanmontevista204 2 ปีที่แล้ว

    Looking for a great explanation for this topic.Good thing i found this one .Thank you very much doc.

  • @faoizashraf1027
    @faoizashraf1027 4 ปีที่แล้ว

    can you please solve the following:
    summition n ranges from 0 to infinity ((X^2+3)/12)^n , using root test .... find interval and radius of convergence.....

  • @libelldrian173
    @libelldrian173 2 ปีที่แล้ว

    My professors script says that when using the ratio test for power series its limit L gives us the radius of convergence as 1/L for all L of (0,+oo). So it would mean that for a limit of 1 the radius of convergence would be 1 not inconclusive as you said. 🤔

  • @emc2884
    @emc2884 2 ปีที่แล้ว

    Thanks sir for your extraordinary explanation really we are gifted you by the God to understand the topics of math in such a easy way God bless you and keep growing up.

  • @tangpiseth8416
    @tangpiseth8416 3 ปีที่แล้ว

    Can we also use the ratio test to find the Radius of convergence? like R=lim of absolute value of an+1/an?

  • @tobiaspollner9105
    @tobiaspollner9105 ปีที่แล้ว

    Last example : why do you say that 0 times infinity is 0?

    • @fahrenheit2101
      @fahrenheit2101 ปีที่แล้ว

      Plugging in x=2
      You get the limit of something that is always 0 no matter what the value of n. The limit of 0 is, well, 0
      In contrast, something like e^-n × n
      is the product of something approaching 0, and something approaching infinity. This is different, and you need to compare their growth rates (using L'hopital's or something), in order to determine the 'winner', so to speak.

  • @christopherabdelhay959
    @christopherabdelhay959 ปีที่แล้ว

    very good explanation keep up the good work

  • @AvaBasileo
    @AvaBasileo 4 หลายเดือนก่อน

    I can't beiieve you explained this so well in nine minutes. Thank you!

  • @reneemiriam8552
    @reneemiriam8552 4 ปีที่แล้ว

    Hi Trevor ..Please do videos on topology and functional analysis

  • @emtikamal6593
    @emtikamal6593 2 ปีที่แล้ว

    Becoming your fan day by day sir❤️

  • @SG-dw8jh
    @SG-dw8jh 2 ปีที่แล้ว

    |1-2| =1 why was -1 one plugged in?

  • @peterelkhoury4624
    @peterelkhoury4624 ปีที่แล้ว

    Amazing!

  • @ethanedgington3561
    @ethanedgington3561 2 ปีที่แล้ว +3

    My college cal II teacher never actually went through explaining how to tell if the divergent end is equal to the parameters or not. You, sir, taught me in six minutes! Thank you so much!

  • @ellen128
    @ellen128 2 ปีที่แล้ว +3

    I always liked how you put advanced math concepts in perspective easily and smoothly. Connecting the dots greatly enhances my understanding. Thank you!!!