Oxford Calculus: Taylor's Theorem Explained with Examples and Derivation

University of Oxford mathematician Dr Tom Crawford derives Taylor's Theorem for approximating any function as a polynomial and explains how the expansion works with two detailed examples.
Test yourself with some exercises on Taylor's Theorem with this FREE worksheet in Maple Learn: learn.maplesoft.com/?d=COGRDG...
The video begins by introducing the idea of approximating a function by a polynomial and the condition we choose to implement that allows the coefficients to be derived. By ensuring that both the function and polynomial approximation are equal for all derivatives at a single point, Cauchy's Mean Value Theorem can be applied to give equality.
Taylor's Theorem is demonstrated with two fully worked examples. First, the power series expansion for cos is derived by expanding around zero. Next, a third degree polynomial approximation is calculated for small x, when expanding the function ln(1+sin(x)).
Check your working using the Maple Calculator App - available for free on Google Play and the App Store.
Android: play.google.com/store/apps/de...
Apple: apps.apple.com/us/app/maple-c...
Other videos in the Oxford Calculus series can be found here: • Oxford Calculus
Finding critical points for functions of several variables: • Oxford Calculus: Findi...
Classifying critical points using the method of the discriminant: • Oxford Calculus: Class...
Partial differentiation explained: • Oxford Calculus: Parti...
Second order linear differential equations: • Oxford Mathematics Ope...
Integrating factors explained: • Oxford Calculus: Integ...
Solving simple PDEs: • Oxford Calculus: Solvi...
Jacobians explained: • Oxford Calculus: Jacob...
Separation of variables integration technique explained: • Oxford Calculus: Separ...
Solving homogeneous first order differential equations: • Oxford Calculus: Solvi...
Find out more about the Maple Calculator App and Maple Learn on the Maplesoft KZread channel: / @maplesoft
Produced by Dr Tom Crawford at the University of Oxford. Tom is an Early-Career Teaching and Outreach Fellow at St Edmund Hall: www.seh.ox.ac.uk/people/tom-c...
For more maths content check out Tom's website tomrocksmaths.com/
You can also follow Tom on Facebook, Twitter and Instagram @tomrocksmaths.
/ tomrocksmaths
/ tomrocksmaths
/ tomrocksmaths
Get your Tom Rocks Maths merchandise here:
beautifulequations.net/collec...

Пікірлер: 106

  • @febobartoli
    @febobartoli2 жыл бұрын

    A concise and cogent summary! I remember this from about 30 years ago in University. Lovely. Absolutely essential when developing functions in modeling physical phenomena for me as an amateur science buff.

  • @RC32Smiths01
    @RC32Smiths012 жыл бұрын

    Always interesting in the Taylor's Theorem. Never got around to learning it in Uni :( But great job on always explaining in fun detail

  • @Cindy-tu2it
    @Cindy-tu2it2 жыл бұрын

    Loved this! Very clear explanation, and enjoyed the pace at which you speak.

  • @rushikeshgadewar3155
    @rushikeshgadewar31552 жыл бұрын

    This was quite helpful for revising the topic for my engineering mathematics paper. Thanks from a fellow engineering student 🇮🇳

  • @juliusteo
    @juliusteo2 жыл бұрын

    I remember "learning" Taylor series in university but didn't grasp the concept. I could replicate the steps but didn't actually understand what I was doing. 😅 Now I (think) I know! Thanks, Tom! Subscribed!

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    Glad it was helpful!

  • @abbe23456789
    @abbe234567892 жыл бұрын

    Excellent video as always, keep them coming!

  • @diego7425
    @diego74252 жыл бұрын

    I’m going to see Taylor Series at my Uni in a few months! This video is like a blessing !

  • @0623ankara
    @0623ankara Жыл бұрын

    Hello, I found the video you uploaded about calculus really useful and I would like to thank you for the valuable information you shared with us, but I have a suggestion for you to have this video in more streams. It also expands your subtitle options. Thanks in advance

  • @mahneh7121
    @mahneh71218 ай бұрын

    great video, i've just noticed that when we approximate cos(x ) = 1 - x^2/2, this indeed is a parabola pointing down, which is what you see if you plot cos(x), close to 0. We can also see why it would start failing badly after +-pi/2, since that approximation is not periodic.

  • @maxcaddis4254
    @maxcaddis42542 жыл бұрын

    As an AS student this hurt my brain 🤯 Think I should come back in a couple years...

  • @mtahausman

    @mtahausman

    Ай бұрын

    This isn't a part of AS right?

  • @adhiyanthaprabhujeyashanka2091
    @adhiyanthaprabhujeyashanka2091 Жыл бұрын

    Very easy to understand, thank you sir for uploading

  • @reubenrobots6352
    @reubenrobots6352 Жыл бұрын

    Hi Tom, great explanation. Do you have worked solutions for the question sheet? Thanks!

  • @saeedelghaziri2385
    @saeedelghaziri23852 жыл бұрын

    this is so beautifully done, i’m in sixth form and this is crazy interesting

  • @bannerstrike868
    @bannerstrike8686 ай бұрын

    Thank you!! Very insightful video

  • @anawilliams1332
    @anawilliams13322 жыл бұрын

    Hey tom, curently in year 12 looking at the maclaurin expansion, unfortunatly we dont do the taylor series at a level maths or futher maths but i always wanted to learn it so i found this awsome. Keep up the great work, also cant wait too see you saturday :)

  • @InexorableVideos

    @InexorableVideos

    2 жыл бұрын

    What exam board are you doing? I know Taylor series is in Edexcel if you opt for further pure 1

  • @anawilliams1332

    @anawilliams1332

    2 жыл бұрын

    @@InexorableVideos aqa :( we have a higher focus on statistics and mechanics

  • @InexorableVideos

    @InexorableVideos

    2 жыл бұрын

    @@anawilliams1332 ah that's a shame. If you are really interested in more pure stuff there is technically nothing stopping you from getting an Edexcel further pure 1 book and doing bits of it for fun. If you wanna go to uni to do anything in STEM I would say Taylor series is mega helpful

  • @anawilliams1332

    @anawilliams1332

    2 жыл бұрын

    @@InexorableVideos yeah its really the key to approximations. In the summer between year 12 and year 13 i want too look at it

  • @gamerjojo4591
    @gamerjojo45912 жыл бұрын

    I had this in my previous semester , it was pretty fun doing it ngl

  • @BruceWayne-qj3nv
    @BruceWayne-qj3nv2 жыл бұрын

    At 11:00 Could someone explain how “Cauchy’s Mean Value Theorem” requires Pn(x) to be a infinite polynomial?

  • @zeldovich33
    @zeldovich332 жыл бұрын

    Think that is one of the most powerful tools for applied mathematicians and the most underrated

  • @exoticcoder5365
    @exoticcoder53658 ай бұрын

    Maple Learn Calculator is a Life Safer, I can't believe it's free

  • @johnchessant3012
    @johnchessant30122 жыл бұрын

    To get the first few terms for log(1+sinx) it might be easier to substitute the series for sinx into the series for log(1+x). log(1+x) = x - x^2/2 + x^3/3 - ..., and sinx = x - x^3/6 + ... -> log(1+sinx) = (x - x^3/6) - (x - x^3/6)^2/2 + (x - x^3/6)^3/3 = x - x^2/2 + x^3/6 + ... Here we used degree-3 polynomials for log(1+x) and sinx so our result for log(1+sinx) will be accurate up to the x^3 term

  • @andrewhaldenby4949
    @andrewhaldenby49492 жыл бұрын

    Beautiful Tom ty!

  • @user-xl1ig1bn6i
    @user-xl1ig1bn6i5 ай бұрын

    For once, I could get the gist of Taylors Theorem. I have looking it up all over the internet. Thank you for the vedio explanation.

  • @davidgould9431
    @davidgould94312 жыл бұрын

    24:00 The derivatives are only getting more complicated because no simplification has been done, which sounds like a tautology. However, (-cos² x)/(1+sin x)² - sin x/(1 + sin x) = -(1 + sin x)/(1 + sin x)² and, because we are interested in small x, so (1 + sin x) ≠ 0, we get -1/(1 + sin x) which differentiates to (cos x)/(1 + sin x)² Without cancelling the (1 + sin x), you get the derivative (cos x)(1 + sin x)²/(1 + sin x)⁴ which is almost what maple's long answer simplifies to: it gives (cos x)(1 + sin x)/(1 + sin x)³ which is one factor fewer of (1 + sin x) top and bottom. Unless I've messed up my algebra somewhere. At the end of the day, unless playing with algebra is your way of relaxing, I guess it's easier and more reliable to just use a tool. :-)

  • @Jo-bx6ez
    @Jo-bx6ez5 ай бұрын

    At 4:29 what happened to the a(n) coefficient in the k-th term of the second derivative?

  • @karinablanchard9511
    @karinablanchard9511 Жыл бұрын

    A million thank yous! This is awesome!

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    Glad it was helpful!

  • @noonespecial3536
    @noonespecial35365 ай бұрын

    Great video Tom! But I still don't get what it means to expand around a. Why don't we just leave it at x? Why is the Maclaurin series at a=0?

  • @nicholasdavies6264
    @nicholasdavies62642 жыл бұрын

    Tom, your footage is superb and thank you for that. Can I ask if you teach Physics along with your mathematics? 👍

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    I just teach maths, but I do a lot of the physics-type topics such as quantum theory and relativity

  • @brummi9869
    @brummi9869 Жыл бұрын

    Could we say that in the limit, as n approaches infinity, any function f(x) equals the Taylor series of that function? Edit: continuus function f, if f is not continuus at a point, then I think the taylor series wont reach it, no matter of how many terms it consists

  • @JinkusuDutchman
    @JinkusuDutchman6 ай бұрын

    Tom, can you verify that the derivative of 1/(1+sin(x)) is -(cos(x)^2)/(1+sin (x))^2 because when i calculate it manually and use a calculator the numerator is not squared.

  • @Renat9453
    @Renat9453 Жыл бұрын

    Amazing! Thank you very much😃

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    You're welcome 😊

  • @actualBIAS
    @actualBIAS5 ай бұрын

    It is very interesting to see that calculus apparently exists. In germany in CS we learn Analysis 1 + 2 + 3. I developed this strange paranoia that on every corner there's a proof to do.

  • @rajveerajmani
    @rajveerajmani Жыл бұрын

    god !! this is really really difficult , seriously just missed this out in college and it feels like ive been left a light year behind everyone else

  • @under88Me
    @under88Me9 ай бұрын

    Didn't know that Machine Gun Kelly's music career failed and he became a math professor instead.

  • @OakStump
    @OakStump9 ай бұрын

    The worksheet is not available. I just get taken to the Maple start screen and no worksheet. Please check. Thanks.

  • @carviryzen288
    @carviryzen288 Жыл бұрын

    For the cos(x) expansion, why is a equal to zero?

  • @joshuapasa4229
    @joshuapasa42292 жыл бұрын

    How would you prove that the error of the taylor series goes to 0 as n goes to infinity?

  • @jinnjinn5567
    @jinnjinn5567 Жыл бұрын

    Might be useful for students to memorize the easiest Maclaurin series off of Wikipedia; - sin, cos, sinh, cosh, arctan, arctanh - e^x, ln(1-x), ln(1+x) - 1/(1-x), 1/(1-x)^2, 1/(1-x)^3 There are common patterns between Maclaurin series of some functions, with only slight differences such as adding/removing (-1)^n or adding/removing a factorial for the denominator.

  • @flsal27
    @flsal272 жыл бұрын

    4:28 is there a a n missing?

  • @justanormalyoutubeuser3868
    @justanormalyoutubeuser38682 жыл бұрын

    I was hoping for an actual proof of why the power series actually converges to the value of the function for any input in the dominion (provided the function is continuous and differentiable infinitely many times).

  • @gabrielprelaz1290
    @gabrielprelaz12902 жыл бұрын

    nice vid!

  • @tridivsharma2342
    @tridivsharma23422 жыл бұрын

    tom can you please do a video on the laplacian, please

  • @pitiwatkittiwimonchai4656
    @pitiwatkittiwimonchai46562 жыл бұрын

    Nice sir

  • @mictecacihuat665
    @mictecacihuat665 Жыл бұрын

    One version of Taylor's theorem that doesn't get talked about much is the multivariable one. I think books just assume that if you know the single-variable version then you can extend it to the multivariable domain but I don't think that's quite true...

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    The same principles still hold as long as you’re careful with those partial derivatives!

  • @mictecacihuat665

    @mictecacihuat665

    Жыл бұрын

    @@TomRocksMaths yup, it’s just tricky!

  • @gui_funky8503
    @gui_funky85032 жыл бұрын

    Next one could be fourier series, that has a similar idea

  • @TomRocksMaths
    @TomRocksMaths2 жыл бұрын

    Test yourself with some exercises on Taylor's Theorem with this FREE worksheet in Maple Learn: learn.maplesoft.com/?d=CFBSHQOGDODGKJHTHOMHGFBTIKNTKIISOJNIGONSILHHPHEQFUERNSGQHHEKLFPKGRINBJJNJTESJNHPCOKKEQOIJTMRJNLUCNPO

  • @tj_h3005
    @tj_h30052 жыл бұрын

    This is the explanation I needed in 2nd year. Now I just need someone to explain what those Epsilon Delta proofs were about.

  • @user-xl1ig1bn6i

    @user-xl1ig1bn6i

    5 ай бұрын

    That's easy. So many math KZreadrs have made vedios for epsilon delta proofs and epsilon delta worked examples. Just Google it!

  • @oneshot2028
    @oneshot20282 жыл бұрын

    Hi Tom, I have a question on the Yang-Mills and Mass gap Millennium prize problem. So if somebody solves this problem will he get the Nobel Prize or the Fields medal??

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    Fields medal as there isn't a Nobel prize for maths unfortunately.

  • @Stephen_2330
    @Stephen_23302 жыл бұрын

    Hey Tom, I would suggest for a video try explaining or solving problems with Foo Fighters songs as background music. Would you like to do it someday?

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    youtube copyright might have something to say about that... (I do love the Foo fighters though!)

  • @Stephen_2330

    @Stephen_2330

    Жыл бұрын

    @@TomRocksMaths Hoping copyright does not bring the Channel down, it would be so cool!

  • @reubenrobots6352

    @reubenrobots6352

    Жыл бұрын

    @@TomRocksMaths "and if we extend this series to n = infinity (Everlong)..."

  • @melanierhianna
    @melanierhianna2 жыл бұрын

    Just refreshing my maths skills. I did physics and astronomy at Uni. It’s been 40 years since I did this. I feel old.

  • @melanierhianna

    @melanierhianna

    2 жыл бұрын

    I remember using this to approximate operations on early computers with limited math libraries. Isn’t this why we use radians because the approximation is more accurate for small values of x. Also can’t you, using the series for cos, sin, and e, together with complex numbers, derive Euler’s formula, -e^-iPI = 1?

  • @davidplanet3919

    @davidplanet3919

    2 жыл бұрын

    You can do that if you define exp( i x) as a power series.

  • @sumitjangir528
    @sumitjangir5282 жыл бұрын

    Make a video on application of calculus

  • @skyscraperfan
    @skyscraperfan2 жыл бұрын

    Does that also mean that if for two differentiable functions in one point all derivatives are equal, both functions are equal in very point? That is quite mind blowing, because it means that you can define every function through a single point.

  • @VenkataB123

    @VenkataB123

    2 жыл бұрын

    Dunno if I understood it right, but if you mean to say that if two functions have the same derivative at a point, the functions are equal (and that's how we can define any function through the same point), that can't be true. If we consider a function f(x), then f(x) + a (where a is some constant) for any value of 'a' will have the same derivative. But, that doesn't mean they are the same function. Like, sinx+1 doesn't equal sinx+120.

  • @drslyone

    @drslyone

    Жыл бұрын

    For analytic functions, if you know all derivatives at a point, then that describes the function (within the interval of convergence). This is the definition on an analytic function, a function that has a power series representation. Most functions you see are analytic at least in some open interval. (Note: all derivatives includes the 0th derivative, so they won't differ by a constant. ) But there are infinitely differentiable functions that are not analytic, and knowing all derivatives at a point doesn't distinguish them.

  • @log8746

    @log8746

    4 ай бұрын

    No, the expression that we set for the 'kth' derivative of our approximating polynomial at 'a' must hold true for any value of k from 0 till n. That is our rule.

  • @l_a_h797
    @l_a_h7973 ай бұрын

    The explanations of Taylor polynomials are helpful, and well-thought-out. Unfortunately the title of the video is "Taylor's Theorem," which gets very short (even misleading) shrift in this presentation. Taylor's Theorem is much more specific than "the approximation gets closer to f(x) the more terms you add." I came here to learn and understand the theorem, and was disappointed to find that the video doesn't live up to its title. If the video were titled "Taylor approximations" or "Taylor polynomials", it would live up to its advertising, and would not mislead people who are looking for an explanation of Taylor's theorem. BTW, the "FREE" Maple Learn worksheet doesn't deliver: even once you create an account, you can't view the worksheet (view limit reached for "this limited trial version").

  • @navinsubba7169
    @navinsubba71692 жыл бұрын

    Awesome 👍

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    Thanks 🤗

  • @samocali
    @samocali2 жыл бұрын

    I think maple might be my new best friend

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    it's awesome isn't it?

  • @StephenMarkTurner
    @StephenMarkTurner5 ай бұрын

    Back in my day (Waterloo in the 80s), when the prof mentioned Taylor Series, the class would gently booooo. Never really sure why.

  • @mlam4221
    @mlam42212 жыл бұрын

    What does “expanding around a point a “ means?

  • @VenkataB123

    @VenkataB123

    2 жыл бұрын

    Probably means to define the polynomial "in the neighbourhood" of that point. In the sense that when we expand around "a", we make all values really close to "a" permissable. That's why the Taylor expansion Tom wrote for cosx and ln(1+sinx) only work for a

  • @itsreeah2663
    @itsreeah26632 жыл бұрын

    The people called Taylor who are watching: does someone say my name?

  • @AmanSingh-lv9qp
    @AmanSingh-lv9qp6 ай бұрын

    Such a beauty

  • @pritamnag6666
    @pritamnag6666 Жыл бұрын

    I just see your video and like

  • @qualquan
    @qualquan Жыл бұрын

    Rather than using any assumptions why not derive Taylor/McLaurin from 1st principles thus justifying the polynomial? Why not begin with the obvious concept that theoretically any F(X) = the power integral of F^1(M^1) . (X-a)/1! where F^1(M^1) represents an implicit mean derivative Since F^1 (M^1) is not explicit we replace it with F^1(a) whose numerical value is explicit. But power integrating F^1 (a) results in an error = F^1(M^1) minus F^1(a) . (X-a). But the difference between F^1(M^1) and F^1(a) is a construct of the next higher derivative i.e. F^2. This is the precise reason why we then try to reduce this error by taking Numerical (explicit) F^2(a) and power integrating it (twice) = F^2 (a)/2! . (X-a)^2 thus creating the next term of the Polynomial P2 (X). A smaller error = F^2(M^2) minus F^2(a) . (X-a)^2/2! will remain which in turn is reduced by the next higher iteration of the above steps, successively reducing a declining error with each iteration. The n Factorial in the divisor is part and parcel of the progressive Power Integration of F^n(a) over (X-a)^n. Thus no novel assumptions are used in developing the Taylor polynomial which incidentally uses the easiest of integrals namely Power integrals. rivative = F^2(a)

  • @adriang.4628
    @adriang.46285 ай бұрын

    (Taylor's Version)

  • @mclovin6537
    @mclovin6537 Жыл бұрын

    youre like the anime professor of math professors

  • @TomRocksMaths

    @TomRocksMaths

    Жыл бұрын

    I’ll take it

  • @likemath.
    @likemath.2 жыл бұрын

    Khai triển hàm số có ý nghĩa gì.

  • @jonathanv.hoffmann3089
    @jonathanv.hoffmann30895 ай бұрын

    🎉 🎉🎉 🎉🎉🎉

  • @ricardoguddemartins5420
    @ricardoguddemartins54202 жыл бұрын

    It is not easy! The worst part is to calculate the derivatives.

  • @enzeru97
    @enzeru976 ай бұрын

    I don't mean to be a prick, but you forgot a "an" right at 4:30.

  • @omarthealgerian9942
    @omarthealgerian99425 ай бұрын

    Ayaa inelec student win rakom

  • @whatever-ot3ez
    @whatever-ot3ez Жыл бұрын

    Slaaaay

  • @mariadelourdesaniessanchez1473
    @mariadelourdesaniessanchez1473 Жыл бұрын

    for me I finish the school but my color is pink

  • @sebastianbalbo1906
    @sebastianbalbo190610 ай бұрын

    Madhava serie

  • @yuji3171
    @yuji31712 жыл бұрын

    In Asia you probably learn this at age 15 😔

  • @janav5624

    @janav5624

    2 жыл бұрын

    Are u kidding me?? Really

  • @VenkataB123

    @VenkataB123

    2 жыл бұрын

    Uhh nope. I'm Asian and this is the first time I'm learning this. Hasn't even been taught to me in college but I thought I'd learn it because why not?

  • @janav5624

    @janav5624

    2 жыл бұрын

    @@VenkataB123 ye same

  • @janav5624

    @janav5624

    2 жыл бұрын

    @@VenkataB123 even i am from Asia India but I am in 8th but till ik in furthrr classes there is no taylor series...... I just heard of trigonometry and other theorems

  • @VenkataB123

    @VenkataB123

    2 жыл бұрын

    @@janav5624 True. I'm completing my 12th this year and though we have a bit of trigonometry with calculus, we don't have Taylor series. So yeah, the person who wrote the original comment must be bluffing😂

  • @supravobiswas
    @supravobiswas Жыл бұрын

    sir btw you dont like a teacher or a proff here in india its like different

  • @YashPradhan-iq5mp
    @YashPradhan-iq5mp Жыл бұрын

    please stop writing downwards

  • @Max-E-Mum

    @Max-E-Mum

    Жыл бұрын

    how do u write upwards?

  • @daddyiscummin
    @daddyiscumminАй бұрын

    r/jeeneetatrds