Solving all the integrals from the 2023 MIT integration bee finals

แชร์
ฝัง
  • เผยแพร่เมื่อ 24 ธ.ค. 2024

ความคิดเห็น • 423

  • @maths_505
    @maths_505  ปีที่แล้ว +364

    I made a mistake while editing the video:
    For the 2nd integral, use double angle formulae for sin2x, sin6x, sin10x and sin30x to get the integral on line 2 at the 4:51 mark. The solution development for this integral is credited to my friend Myers
    Solutions for the 2024 finals:
    th-cam.com/video/QaI38XOsqL0/w-d-xo.htmlsi=UBudXz7fv9LOAS8z

    • @jackychanmaths
      @jackychanmaths ปีที่แล้ว

      Where's the floor function in Q4?

    • @maths_505
      @maths_505  ปีที่แล้ว +13

      Left as an exercise for the reader. Its actually not that hard.

    • @kurrurin
      @kurrurin ปีที่แล้ว

      i,.

    • @jackegan9947
      @jackegan9947 ปีที่แล้ว

      🙄

    • @sharp_object
      @sharp_object ปีที่แล้ว +13

      i like your funny words magic man

  • @domc3743
    @domc3743 ปีที่แล้ว +556

    The way luke just stands there scribbling the odd thing on the board every now and then and doing everything mentally is breathtaking in a way, what a talent. Appreciate you solving these integrals for our pleasure

  • @analysis726
    @analysis726 ปีที่แล้ว +176

    i could’ve never figured out factoring out cos^2 from (sinx+cosx)^2 in the first problem in order to set up a u-substitution. it’s such a nice, simple solution that requires just a bit of outside the box thinking to find.

    • @kawamann1234
      @kawamann1234 ปีที่แล้ว +9

      i still dont get how this factorization works out

    • @kawamann1234
      @kawamann1234 ปีที่แล้ว

      ah nevermind i got it ...haha

    • @familyfamily6037
      @familyfamily6037 ปีที่แล้ว

      @@kawamann1234 how does it work

    • @kawamann1234
      @kawamann1234 ปีที่แล้ว

      when you are going to factor out the cosine, you need to take care about the power of 2 of the whole expression. Try writing it simpler and add more steps by writing it as whole like (sinx+cosx)(sinx+cosx). When i did that i could see it immediately. But just in case: This leads to cosx(sinx/cosx + 1)*cosx(sinx/cosx + 1) then you see its the same expression twice and there you go. @@familyfamily6037

    • @muditchaturvedi5276
      @muditchaturvedi5276 10 หลายเดือนก่อน

      Exactly why to go for beta and gamma fns. ......

  • @cupidstunt22
    @cupidstunt22 ปีที่แล้ว +2002

    You lost me at Ladies and Gentlemen...

  • @kutubkhanbhatiya4573
    @kutubkhanbhatiya4573 ปีที่แล้ว +10

    Ohh man I was searching for the solutions of these integrals for a long time.
    Thankss

  • @eobardthawne19
    @eobardthawne19 ปีที่แล้ว +158

    The fact you are going through so much effort to post out these high quality videos is insane! Keep up the good work and ima bet you are gonna grow faster than Ray's function ( well not actually tho lol that wud blow up TH-cam servers)

    • @Kuzmo
      @Kuzmo ปีที่แล้ว

      whats rays function

    • @NoceurXeno
      @NoceurXeno ปีที่แล้ว

      Yeah, what's ray's function????

    • @eobardthawne19
      @eobardthawne19 ปีที่แล้ว

      @@NoceurXeno rayo's function

  • @manstuckinabox3679
    @manstuckinabox3679 ปีที่แล้ว +19

    Bro the Square decomposition was a new thing to me lol! and that last one was just mind boggling!

  • @polyreza
    @polyreza ปีที่แล้ว +51

    I really enjoyed solving the last integral, the monster one😂 It was something completely new to me. Thank you

    • @SunnyRosy-uk1ch
      @SunnyRosy-uk1ch 10 หลายเดือนก่อน +2

      Id say the last one is the simplest to solve at first glance for MIT level students in an exam as once you get that it's an infinite GP, then the question gets solved in like at max 4-5 steps

  • @IndranilBiswas_
    @IndranilBiswas_ ปีที่แล้ว +142

    What beautiful integrals!! Calculus is where trigonometry really shines as an elegant and versatile subject. Who would have thought you could derive so much utility from Pythagoras's theorem!

    • @Wosndolousn
      @Wosndolousn ปีที่แล้ว

      The fuck you guys talking about?

  • @jasiek1405
    @jasiek1405 ปีที่แล้ว +89

    I understood absolutely nothing, I don't even know what an integral is, yet I enjoyed this video so much

    • @maths_505
      @maths_505  ปีที่แล้ว +18

      😂😂😂....I'm glad you had fun

    • @Ligatmarping
      @Ligatmarping ปีที่แล้ว +29

      Well, this are certainly NOT the first integrals you should try to solve when you learn what they are xd. They are beautiful and the video is very good, but there are a lot of simpler ones to practice.

    • @michaelblankenau3129
      @michaelblankenau3129 ปีที่แล้ว +8

      Same here . I keep expecting that through osmosis I’ll be able to understand some of it… but it never happens

    • @yuyuvybz
      @yuyuvybz 6 หลายเดือนก่อน

      How good is your integration now 👀
      I want to see how good I'll be in 1 yr too.

  • @martinepstein9826
    @martinepstein9826 9 หลายเดือนก่อน +1

    At 10:07 here is a quick way to see int_[0 to pi] 4 cos^2(8x) dx = 2pi. By periodicity it's clear that if we replace cos with sin we get the same answer. Now if we add we get
    2*answer = int_[0 to pi] 4(cos^2(8x) + sin^2(8x)) dx = int_[0 to pi] 4 dx = 4pi
    Therefore the answer is 2pi.

  • @hozinryu
    @hozinryu ปีที่แล้ว +3

    In the second integration, I remembered the orthogonality of the cosine function, being able to effectively cancel out a few terms!!

  • @petrie911
    @petrie911 ปีที่แล้ว +4

    For problem 2, it's easier if you substitute u = 2x so that the integral covers a full period of cosine. Then once you have your sum you can use the orthogonality of Fourier series terms. It also saves a lot of extra 2s in the intermediate calculations.

  • @johnchessant3012
    @johnchessant3012 ปีที่แล้ว +79

    Very nice video! Just a note, Q4 required the contestants to find the exact value of the floor of the answer, so you'd need to do a series expansion to a few terms and check that your residual is less than 1. Elementary but very tedious haha

  • @TUMATATAN
    @TUMATATAN ปีที่แล้ว +5

    Wow, I can attest there were SOME words in English...I believe in the beginning he said "Ladies and Gentlemen..."

  • @two697
    @two697 ปีที่แล้ว +507

    I'm surprised they were able to answer the last one but none of the first 4 integrals. I would say that the last integral was the hardest

    • @jhadhiraj147
      @jhadhiraj147 ปีที่แล้ว +3

      Last one is straight forward bro. 3:08

    • @oumguptahello
      @oumguptahello ปีที่แล้ว +1

      @@jhadhiraj147 can you elaborate it please?

    • @Pal_yt
      @Pal_yt ปีที่แล้ว +49

      If you're Asian then you could arrive the answer without picking the pen.

    • @__Hanasei__Levinus__
      @__Hanasei__Levinus__ ปีที่แล้ว

      @@Pal_yt hey hey, I know it's a joke, but tone down the american racism a little bit... We don't need anymore people coming from asia have societal expectations imbibing us with this silly pressure in regards to mathematics, lolol.
      ...seriously, I don't want strangers to expect me to solve these kinds of problems, and then be laughed at, and then looked at, as someone who is silly and weird....

    • @clvsidy
      @clvsidy ปีที่แล้ว +2

      @@Pal_ytLMAO

  • @Ligatmarping
    @Ligatmarping ปีที่แล้ว +13

    Great video! My favourites are also the third one and the fifth one (in the order you make them on the video). This are the ones with the really nice ideas in the solution. The fifth one's idea of comparing to the integral from 0 to 1/2 is kinda natural thanks to the 2^n in the sum. The third one is the one I wouldn't have a big hope of getting something nice while trying to get a and b haha, but it works.

  • @tikarai4060
    @tikarai4060 ปีที่แล้ว +3

    Interestingly solved! Great video. My favorite ones are 2 and 5. Thanks a lot.

  • @김현규-e4v
    @김현규-e4v ปีที่แล้ว +2

    Fantastic video: It definitely makes me study much harder than I used to-

  • @sanchitlodha5770
    @sanchitlodha5770 ปีที่แล้ว +2

    in the third question when we get 2rootof ab we could just have added and subtracted x^2 in the root of the rhs and then use a^2-b^2=(a-b)(a+b) to factorize and take a 2 outside the root to immediately find the and b quicker is what i think

  • @wondrousparrot2815
    @wondrousparrot2815 ปีที่แล้ว +3

    Idk why I’m watching this as I’m in precalc but this is some dark magic holy shit.

  • @jabunapg1387
    @jabunapg1387 ปีที่แล้ว +2

    Amazing! The last Integral was cool.

  • @worldblazin4209
    @worldblazin4209 ปีที่แล้ว +2

    Woah this very well amazing. Thanks for MIT Integration this year and solving all problems. 🥰🥰😝

  • @zhato3377
    @zhato3377 หลายเดือนก่อน

    How did you manage to break me before 3 seconds of videos with just "ladies and gentlemen" LMAO, simply absolute cinema.

  • @mohammadalkousa2856
    @mohammadalkousa2856 ปีที่แล้ว +2

    Many thanks, useful video!
    Also for the qualifying tests of the MIT Integration Bee. Recently it was published a book with a title (MIT Integration Bee :Solutions of Qualifying Tests from 2010 to 2023 ), it is very useful

    • @louisl7245
      @louisl7245 ปีที่แล้ว

      May I know where can I download that book? Thanks

  • @MrGreenWhiteRedTulip
    @MrGreenWhiteRedTulip ปีที่แล้ว +9

    Thank you for this video, amazing content! My integration isn’t good enough to follow the bee itself but this kind of video really helps me enjoy it! You have earned a new subscriber :D

  • @insouciantFox
    @insouciantFox ปีที่แล้ว +4

    I might have used Euler substitution at the sqrt(x²±x+1). It happens so rarely but is so satisfying

  • @matei_woold_wewu
    @matei_woold_wewu 7 หลายเดือนก่อน +1

    Summation inside of an integral

  • @MrBhupsa197604
    @MrBhupsa197604 ปีที่แล้ว

    Q3. Let, V m, n in R three functions are defined by
    f(m, n) = integrate x * (m * x ^ (1 / n) - n * x ^ (1 / m)) ^ ((- (m + n))/(m + n + 2mn)) * (x ^ (1 / m) - x ^ (1 / n)) dx from 1 to 2 g_{1}(m, n) = f(m, 1) - f(2, n) And g_{2}(m, n) = f(1, n) - f(m, 2)
    Then the value of [g_{1}(2, 3) + g_{2}(3, 4)] is:. ([.] Denotes the greatest integer function)

  • @porod700
    @porod700 ปีที่แล้ว +6

    Timestamps
    Q1 : 0:11
    Q2 : 4:49
    Q3 : 12:26
    Q4 : 21:24
    Q5 : 25:05

  • @michaelcharlesthearchangel
    @michaelcharlesthearchangel ปีที่แล้ว +1

    The ability to integrate beyond target, is what separates an obtuse predator from an acute producer.

  • @mobinekhtiary9023
    @mobinekhtiary9023 ปีที่แล้ว +1

    The first good math video on youtube ❤❤

  • @venkybabu8140
    @venkybabu8140 ปีที่แล้ว

    All integrals and differentiation is like the gearing systems of a car or watches. Functional transforms and substitution of limits is like the size of the gears and there number of teeth. When limits are changed from one to other it is somewhat like changed number of teeth on the gears and clutches. Functional transforms are like sine cosine etc. the rate of change of functional parameters. Maths is somewhat like that. A gearing systems with dimensions. FofF is dimensions switch. Or base or radical changes.

  • @Animal-yb1rr
    @Animal-yb1rr ปีที่แล้ว +7

    Only bee that I integrated with was a bee that stung me

    • @maths_505
      @maths_505  ปีที่แล้ว +2

      😂😂😂

  • @aaryangupta2328
    @aaryangupta2328 ปีที่แล้ว

    kudos for the efforts!! i hve been finding the solutions to these probs but noone posted a video or something. Thanks

  • @sujals7108
    @sujals7108 ปีที่แล้ว +1

    For the first problem you can simply sub z = u^1/3 and then solve it using elementary techniques!

  • @adnannajeeb5619
    @adnannajeeb5619 ปีที่แล้ว +3

    Thank you so much for this great video. I’m noting down all the techniques to practice them and trying them out on new math problems.
    I really love your video and appreciate what you’re doing. I’m learning a lot from it.

  • @vancedforU
    @vancedforU หลายเดือนก่อน

    21:22
    It is actually ln(2+sqrt(7)/sqrt(3)) at the end, not just 3

  • @mathcanbeeasy
    @mathcanbeeasy ปีที่แล้ว +1

    14 minutes for the last one, given that you had already solved it and presented it as quickly as possible.
    How the hell could anyone have solved it in 4 minutes?

  • @epikherolol8189
    @epikherolol8189 ปีที่แล้ว +3

    Ah this is why I couldn't solve the first one no matter how much I tried.
    I'm a highschool student and here in my country they don't teach u gamma functions and beta stuffs.

  • @avyakthaachar2.718
    @avyakthaachar2.718 ปีที่แล้ว +2

    Thank you so much for this video ❤

  • @oumguptahello
    @oumguptahello ปีที่แล้ว +4

    for the last integral how's the winner able to get to answer really quick without moving much of a hand . Apparently I struggled to assume what to do in it so I took this to my professor he was able to give me the range of this question via sandwich theorem but didn't able to land to on answer.

  • @oo_rahbel_oo
    @oo_rahbel_oo 4 หลายเดือนก่อน

    21:17: Just for the record: The denominator of the logarithm must be the root of 3 instead of 3. Regarding to the last problem: This is the first integral where we know that there is a (closed) solution and mathematica is biting its teeth on it (at least I didn't manage to find any solution using wolfram). Are humans perhaps smarter in the end? Apparently they are at MIT. 😊

  • @theelk801
    @theelk801 ปีที่แล้ว +6

    I would’ve done residue theorem for the second one but I never pass up an opportunity for that

  • @wynautvideos4263
    @wynautvideos4263 ปีที่แล้ว +2

    C’est vraiment incroyable que ils peuvent resoudre celles problèmes aux quatre minutes.

  • @himanshu934
    @himanshu934 ปีที่แล้ว +2

    at 15:05 why didnt you take a - b = +x and a- b = -x as two different cases?

    • @notaslave9628
      @notaslave9628 4 หลายเดือนก่อน

      Maybe we imply that x>0

  • @averagegamer9513
    @averagegamer9513 ปีที่แล้ว +9

    25:02 Are you simply going to skip the floor function part of problem 4? The whole challenge is to find an integer solution to the floor of the answer.
    At 12:02 Small mistake that does not affect the result, but you forgot a factor of 1/2 from the product to sum identity.
    In the end, the result is still 0.
    You could’ve avoided a lot of the mess in problem 5 by simply cancelling the 2^(n-1) and the 2^n at 36:09, leaving 1/2, instead of expanding and inducing errors.

    • @inikew
      @inikew ปีที่แล้ว +13

      bro is the integral paladin

    • @fxz3696
      @fxz3696 ปีที่แล้ว +2

      🤓

  • @suvosengupta4657
    @suvosengupta4657 ปีที่แล้ว +11

    the last integral is something of its own😵‍💫did you have the same reaction while solving🤣:D

    • @maths_505
      @maths_505  ปีที่แล้ว +1

      I definitely enjoyed it

  • @Aman-cg2yt
    @Aman-cg2yt 5 หลายเดือนก่อน

    This integration from Beta and gamma function and good question to explain all how to gama function work 4:52

  • @scratchbeginners4541
    @scratchbeginners4541 5 หลายเดือนก่อน

    I really want to learn those extra techniques for integration(such as Gamma function(????) and Beta Function(????)). Could you recommand any books/videos to learn those life-easing techniques?

  • @createvideo561
    @createvideo561 ปีที่แล้ว

    In case anyone is wondering the integral of first function is (-1/2((((tan(x))^2/9)-1)^1/3)((tan(x))^2/9))-(((((tan(x))^2/9)-1)^1/3)/2((tan(x))^2/9))

  • @entvoker
    @entvoker 6 หลายเดือนก่อน

    Thank you sooooo much. Really appreciate

  • @Jozehkmz
    @Jozehkmz ปีที่แล้ว +11

    Thank you so much for uploading this. Yesterday I found the exercises and I couldn't be calm until I found the solution. Now I can finally rest haha. Great job, keep on going!

  • @nafio2206
    @nafio2206 11 หลายเดือนก่อน +1

    Guys I made it to 1:36 yay. No further tho

  • @abi3135
    @abi3135 ปีที่แล้ว +4

    Isn't the time limit for integration bee finals about four minutes per question? Damn expecting to solve 4:58 in about that time is just cruel

    • @maths_505
      @maths_505  ปีที่แล้ว +8

      1. I'm not as smart as the bois at MIT
      2. They don't have to explain anything while solving😂

    • @two697
      @two697 ปีที่แล้ว +2

      4 minutes is definitely unreasonable for all of them except maybe 1 or 4. Only one of the finalists was able to answer a single integral

    • @abi3135
      @abi3135 ปีที่แล้ว +1

      @@two697 3rd one's possible within 4 minutes i think, if you know the de-nesting formula beforehand instead of deriving it
      √(a ± √b) = √((a + √d)/2) ± √((a - √d)/2), where d = a² - b²

    • @two697
      @two697 ปีที่แล้ว +1

      ​@Abi solving the integral isn't that bad but getting it into the final form is quite cumbersome. Either way, you've basically got to know how solve the integral at first glance as you haven't got time to explore more than one method.

  • @webber9449
    @webber9449 8 หลายเดือนก่อน +1

    crazy how the mit kids do it in like 4 minutes

  • @Agustin-mi6jy
    @Agustin-mi6jy ปีที่แล้ว +2

    That really was a wild ride

  • @XxXK9
    @XxXK9 ปีที่แล้ว +1

    This is beautiful and artistic

  • @trimmy8461
    @trimmy8461 ปีที่แล้ว +1

    I'm pretty proud that you only lost me at the beta and gamma functions

  • @t.gamer0410
    @t.gamer0410 หลายเดือนก่อน +1

    What should I know about integrals for do this kind of integrals.

  • @sickomode6440
    @sickomode6440 5 หลายเดือนก่อน +2

    Literally me during the entire video 8:28

  • @paploox5404
    @paploox5404 ปีที่แล้ว

    14:13 2x^2

  • @umbranocturna6342
    @umbranocturna6342 ปีที่แล้ว

    1:08
    This is very much not clear as day and iam very confused.
    Im not even sure how i got here.

  • @alejandrojimenez108
    @alejandrojimenez108 ปีที่แล้ว +8

    So are you not going to do the fourth problem with the floor function? The floor function is what actually makes it difficult

    • @maths_505
      @maths_505  ปีที่แล้ว +1

      Why would we skip the floor function bit?
      That's the whole point of the integral!

    • @two697
      @two697 ปีที่แล้ว

      ​@@maths_505 he's talking about the question where you let u=x^10. In the original problem, there was a floor around the entire integral

    • @maths_505
      @maths_505  ปีที่แล้ว +3

      Oh that...
      The floor function applies to the solution which makes life much easier....
      It's the 5th problem where we're actually integrating using the properties of the floor function.

    • @alejandrojimenez108
      @alejandrojimenez108 ปีที่แล้ว

      @@maths_505Yes, but how do you evaluate the floor of the answer for that problem?

  • @Db--jt7bt
    @Db--jt7bt ปีที่แล้ว

    There should be a side contest for people integrating with approximations like Riemann Sums and Simpson’s Method.

  • @NaitikNaitikGupta-f9d
    @NaitikNaitikGupta-f9d 10 หลายเดือนก่อน +1

    Honestly problem 6 was done by me but in 15 minutes

  • @joseph-jg2ie
    @joseph-jg2ie ปีที่แล้ว +2

    Where does one learn these unique methods of integration? Im now wondering if I purchased the wrong calc textbook, not sure I remember seeing these tricks...
    (If anyone has any recommendations on how I can level up my game pls lmk)

  • @sophiaisabelle027
    @sophiaisabelle027 3 หลายเดือนก่อน

    This is more complicated than all the problems and issues that I have to deal with.

  • @respectmath95
    @respectmath95 ปีที่แล้ว

    th-cam.com/users/shorts-5Rrl56dBJo?si=DXvyMY02wCR_8iE-
    Here is my attempt to the squared summation integral:
    1. Expand the squared summation and split into 2 parts, the squared terms and the cross product terms
    2.For squared terms, resolve the integer function term by splitting the [0,1] interval into [i/2^n,(i+1)/2^n] for i=0,...,2^n-1
    3.For cross product terms, resolve the integer function term by splitting the [0,1] interval into intervals such that int[(2^i)x] and int[(2^j)x] jumps over the consecutive integer pairs {0,0},{0,1}...,{0,2^(j-i)-1},...,{2^i-1,2^j-1}
    4.Integrate the resolved constant functions term-wise and apply arithmetic & geometric series

  • @SaidThoughts
    @SaidThoughts ปีที่แล้ว +1

    "pretty much clear as day" >.>

  • @AbdullahPunctureWale-BePgCxx
    @AbdullahPunctureWale-BePgCxx 11 หลายเดือนก่อน

    Loved the first one... going to watch the rest... ❤❤

  • @JEE-zm3sh
    @JEE-zm3sh 4 หลายเดือนก่อน

    13:10 Bro u have any idea where i could learn such helpful algebra theories? Any names for these concepts?

    • @yodaas7902
      @yodaas7902 3 หลายเดือนก่อน +1

      Binomial square?

    • @JEE-zm3sh
      @JEE-zm3sh 2 หลายเดือนก่อน

      @@yodaas7902 thanks

    • @JEE-zm3sh
      @JEE-zm3sh 2 หลายเดือนก่อน

      @@yodaas7902 thanks

  •  ปีที่แล้ว

    I am here just to say I saw the thumbnail and immediately started crying from PTSD.

    • @maths_505
      @maths_505  ปีที่แล้ว +1

      Sorry about that mate😂

  • @jyotiradityashukla4569
    @jyotiradityashukla4569 ปีที่แล้ว +1

    Damn!! I was able to answer some of them.

  • @poojankhunt8257
    @poojankhunt8257 ปีที่แล้ว +2

    I had already solved 3 of them before seeing this video, still 2 left to solve......

  • @giuseppemalaguti435
    @giuseppemalaguti435 ปีที่แล้ว +2

    Il primo è semplice B(4/3,2/3)

  • @DiegoTorres-iw5kn
    @DiegoTorres-iw5kn ปีที่แล้ว +1

    WHAT KIND OF WAY IS THAT TO WRITE π

  • @racquelsabesaje4562
    @racquelsabesaje4562 ปีที่แล้ว

    + x y 3/tanx 3+3+3=9 + 3X3=9 x/x=1 1-3/ / pi/2 2 pi /3/9

  • @IroineGrandison
    @IroineGrandison ปีที่แล้ว +9

    Even if you give me a year to solve the last one I would never be able to solve it, thanks a lot mate hope your channel grows more, keep it up

  • @BharatOp007
    @BharatOp007 ปีที่แล้ว

    What is beta and gamma function first time heard about it. I never heard about it earlier

  • @piyushsingh178
    @piyushsingh178 ปีที่แล้ว +1

    Good effort man🎉 In Q3, you'd need to go further ... You'd have to do infinite sum form of log(1+x) upto 3 terms and that will give you the final answer

    • @MONDLIMTHOMBENI-tt2vl
      @MONDLIMTHOMBENI-tt2vl ปีที่แล้ว

      This are long and 😂 what in 4 mins it's what those guys were doing in their heads

  • @jehovah0121
    @jehovah0121 ปีที่แล้ว

    The solution to the first problem demonstrates why I failed again and again via partial fraction stuff...

  • @ttrss
    @ttrss ปีที่แล้ว

    So many times in this video, I pause for a few minutes and then say oh I'm stupid, then continue watching

  • @par22
    @par22 ปีที่แล้ว +3

    Kinda skipped some steps at the start of 2nd problem 4:49 lol

    • @maths_505
      @maths_505  ปีที่แล้ว +1

      Oh damn
      Thanks for pointing that out mate

    • @par22
      @par22 ปีที่แล้ว +1

      @@maths_505 np that's a lot to keep track of lol. good job on the marathon, really impressed with it all, especially that last one

    • @maths_505
      @maths_505  ปีที่แล้ว +2

      @@par22 thanks mate
      For the record going from step 1 to step 2 uses the double angle formula for the sine function

  • @alien77333
    @alien77333 ปีที่แล้ว +4

    Hey can you please tell me what are the uses of such hard integrals in our life? Integrals are useful for finding areas and for physics calculations but these long trigonometric integrals 😐.

    • @maths_505
      @maths_505  ปีที่แล้ว +1

      You'll find lots of tough integrals in higher physics and applied math....these are just like practice problems to help think

    • @alien77333
      @alien77333 ปีที่แล้ว +2

      @@maths_505 After watching this video I had a great discovery. Big enlightenment. I can safely say that I've come to the genius conclusion that I understood nothing.

    • @maths_505
      @maths_505  ปีที่แล้ว

      @@alien77333 😂😂😂😂😂😂😂

  • @ulisesfransiscoparraugueto3194
    @ulisesfransiscoparraugueto3194 ปีที่แล้ว +2

    En el tercer ejercicio te faltó poner al tres dentro de la raíz cuadrada en el resultado final de la integral.

  • @noelani976
    @noelani976 ปีที่แล้ว

    FYI, problem 4 had the whole integral under a FLOOR FUNCTION.

  • @PinoySarisariTV
    @PinoySarisariTV ปีที่แล้ว +2

    I think in 14:03 it should be 2x^2 and not 2x

    • @PinoySarisariTV
      @PinoySarisariTV ปีที่แล้ว +1

      lmao, i should have watch first before leaving this comment. haha. 14:35 it is

  • @WforWill
    @WforWill ปีที่แล้ว +1

    I watched this right after taking Calc AB. Im scared 😂

  • @tiffanyponce1373
    @tiffanyponce1373 ปีที่แล้ว +4

    Question on the first problem you did but how were you able to factor out a (cos(x))^2?
    Wouldn’t redistributing that create (sin(x))^2(cos(x))+cos(x)^2, assuming you include the cos(x) in the denominator of sin(x) to cancel out a cos(x)?
    To add to that, how were you able to include a cos(x) in the denominator of sin(x)? just wondering where that came from.
    Also how were you able to keep the contents in the denominator (tan(x)+1) squared despite factoring out cos(x)^2?
    Generally speaking, I do see how the trig identity of sin/cos creates tan(x) and that 1/cos(x)^2 creates sec(x)^2 but I’m still a little confused on the other aforementioned parts.
    Any answers would be greatly appreciated. Thank you!

    • @簡郁軒-r2p
      @簡郁軒-r2p ปีที่แล้ว

      Expand the (tan + 1)^2 and (sin + cos)^2 , you'll find the answer.

    • @Oufanforever
      @Oufanforever ปีที่แล้ว +3

      sin x + cos x = (cos x) (sin x / cos x + 1) = (cos x) (tan x + 1). Therefore, (sin x + cos x)^2 = (cos x)^2 (tan x + 1)^2

    • @maths_505
      @maths_505  ปีที่แล้ว +5

      (sinx + cosx) = cosx(sinx/cosx + 1) =cosx(tanx + 1)....this implies that
      (sinx + cosx)^2 = (cosx)^2(tanx + 1)^2

  • @sangeetatiwari6007
    @sangeetatiwari6007 ปีที่แล้ว +2

    11th grader me watching it and having absolutely no idea about whatever is going on😂😂😂

  • @racquelsabesaje4562
    @racquelsabesaje4562 ปีที่แล้ว

    /pi 0 ( cosx/cos 3x cos 15x/cos5x)2 dx

  • @stevenmanning2436
    @stevenmanning2436 ปีที่แล้ว

    I wish you were my best friend all throughout my math major.

  • @epicm999
    @epicm999 ปีที่แล้ว

    You forgot to timestamp Q5. It's around 24:13

    • @epicm999
      @epicm999 ปีที่แล้ว

      EDIT: Not sure what I was thinking when I wrote that. It's 25:03

  • @sucim
    @sucim 10 หลายเดือนก่อน

    how the heck do they come up with these integrals that end up in simple solutions?

  • @gel2709
    @gel2709 ปีที่แล้ว +3

    3:27 As a russian, I understand. Sorry about that 😓

    • @Nifton
      @Nifton ปีที่แล้ว +1

      Мне кажется, что здесь это ни при чëм 🙂

    • @gel2709
      @gel2709 ปีที่แล้ว +1

      ​@@Nifton Когда вы написали этот комментарий я тоже как-то осознал, что это скорее всего здесь ни при чём. Я не знаю, я постоянно думаю об этой теме, вот и вылезло. И мне наверное это напомнило ситуацию: Я работаю репетитором по математике и у меня когда началась война один ученик отказывался использовать в задачах вообще букву Z. Через пару недель это прошло конечно, но как-то это воспоминание сразу в голову ударило, когда я смотрел это видео.
      P.S. За Элейну на аватарке однозначно лайк

  • @lyrocon5951
    @lyrocon5951 ปีที่แล้ว +1

    Which program do you used to write on the phone? (i mean the black board)

  • @Youtuber_YusukeFromGermany
    @Youtuber_YusukeFromGermany ปีที่แล้ว +10

    I want a professor like you to make math fun again in university

    • @yuseifudo6075
      @yuseifudo6075 11 หลายเดือนก่อน

      Hello fellow Yu-Gi-Oh fan

    • @Youtuber_YusukeFromGermany
      @Youtuber_YusukeFromGermany 11 หลายเดือนก่อน

      @@yuseifudo6075 I see you are a man of culture as well

  • @maxvangulik1988
    @maxvangulik1988 ปีที่แล้ว

    Naaaa they had to write out the digits in integral 4. There was also a floor function around the whole thing, hence the 10^20.

  • @AdityaMr66
    @AdityaMr66 ปีที่แล้ว

    He is the Formula King!!!