How to Derive The Volume? Hard Geometry Problem

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  • čas přidán 20. 04. 2013
  • mathematicsonline.etsy.com
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    complete explanation for volume of a pyramid here:
    pythagoreanmath.com/deriving-t...
    Sum of integers squared video link:
    • Sum of integers square...

Komentáře • 286

  • @mathematicsonline
    @mathematicsonline  Před 11 lety +99

    The geometry formula videos come from my curiosity to find out where they come from, I search for clues around the web and I share it with you on youtube.

    • @AK-tk1qh
      @AK-tk1qh Před 3 lety +1

      Keep going

    • @arroz2092
      @arroz2092 Před 3 lety +1

      Where should I click to view that too?

    • @sanjeevdutta7760
      @sanjeevdutta7760 Před 3 lety +1

      I watched this because of my curiosity , so please keep going. Best wishes.

  • @gnikola2013
    @gnikola2013 Před 4 lety +209

    This is literally calculating an integral from by definition

    • @egglion7931
      @egglion7931 Před 4 lety +27

      I was expecting some sort of geometry proof but the video was just an integral and I’m like bruh

    • @SonnyBubba
      @SonnyBubba Před 4 lety +41

      It’s also teaching calculus to an audience who might not understand calculus.

    • @oni8337
      @oni8337 Před 2 lety +2

      any pyramid with any simple closed region R as its base and a has a height of h would have a volume of |R|h/3 by means of integration

  • @ptyptypty3
    @ptyptypty3 Před 8 lety +97

    I don't know how you do it, but.. all of your Videos are AMAZING!!... the VISUALS are so important in representing the Intuition.. and YOU HAVE MASTERED that.. Thank YOU!!

    • @user-zk3jc9qr9e
      @user-zk3jc9qr9e Před 4 lety

      Unique Style of Teaching is that a stock image of a teacher? I’m sold

  • @girimumma
    @girimumma Před 4 lety +2

    Rarely seen such a perfect and clear explanation of a mathematical formulae derivation. The voice-over combined with the amazing creativity of the videos explaining visually the words of the voice over - this is totally out of the world. I have subscribed and I will be seeing all your videos and revising my math. Thank you for your videos.

  • @HollywoodF1
    @HollywoodF1 Před 3 lety +3

    This is a great way to introduce calculus. This video, surface of a sphere video, volume of a sphere video. Gives an intuitive sense of what Riemann sums and limit states are actually doing before you start memorizing the integral tricks.

  • @fakherhalim
    @fakherhalim Před 7 lety +24

    The best video -- not skipping a single step! Very visual!

  • @zazkegirotron
    @zazkegirotron Před 7 lety +9

    wow, I've just discovered this channel. This is amazing! thank you for doing all these amazing videos. providing the proof of a concept is essential. and also isn't an easy task. Really happy about finding it. :D

  • @lion321321321321
    @lion321321321321 Před 7 lety +1

    my friend, this visual explanation is the best i have ever seen. Thank you. Keep up the excellent work

  • @naomi1431
    @naomi1431 Před 9 lety +119

    There's a way to cut a unit cube into 6 congruent pyramids, each with a base of 1x1 and a height of 1/2. Each has a volume of 1/6 because it takes 6 of them to make a cube. You can stretch said pyramid to make other square pyramids. (Give it a height of "h" and you have to multiply the height by 2h since it's currently 1/2. A base of l by w means you multiply the volume by l and by w. Thus, you get a volume that is (1/6) x 2h x l x w = (1/3)hlw, without use of limits or large sums or any heavy algebra. This seems a more intuitive approach to me, if you're talking about rectangular pyramids. (Not so with other shapes of bases.. but for an initial introduction. . . ) Thoughts on that?

    • @mathematicsonline
      @mathematicsonline  Před 9 lety +27

      Naomi Anderegg very simple intuitive explanation!

    • @cosmopolitan4598
      @cosmopolitan4598 Před 9 lety +8

      Naomi Anderegg Very smart and simple soluition.But this solution only applies to CUBE
      "There's a way to cut a unit CUBE into 6 congruen...."
      It takes additional trick for brick.
      Good explanation tough, Naomi.

    • @gijsvandelagemaat1604
      @gijsvandelagemaat1604 Před 8 lety +7

      +Stephanus Kusuma The additional trick you mention, is simply SCALING. When you scale an object for example factor 2 in one direction, the volume of that object also increases with factor 2. Since a brick is simply a cube scaled differently in different directions, the same explanation holds: 3 pyramids fit into 1 brick.

    • @kevinjones4924
      @kevinjones4924 Před 8 lety

      +Gijs van de Lagemaat then do it ur self if u think that and if he's doing a bad job than u do it ur self

    • @gupta-pw5xb
      @gupta-pw5xb Před 6 lety +1

      He made another vid. just for this.....

  • @MisterSwagner
    @MisterSwagner Před 11 lety

    These are excellent and extremely well done. From one math teacher to another, you are a superb educator.

  • @arroz2092
    @arroz2092 Před 3 lety

    I watched the video as many times as finally I understood. Thanks for the great job. love this channell will share it with friends too.

  • @Philosophy520
    @Philosophy520 Před 11 lety

    These are amazing videos. Your a genius. Keep it up. I know that you have low video views, but deriving information is very rare, I think. These videos are a necessity in the world.

  • @souvikghosh100
    @souvikghosh100 Před 2 lety +1

    Great explanation with equally good visuals! Loved it and subscribed!

  • @nkctvn
    @nkctvn Před 11 lety

    Please keep making explanation videos like these :(( my textbooks and math teachers seem to ignore the fact that we students need to know WHY, HOW and WHERE these genius formulae come from, too.

  • @wholesomeSloth
    @wholesomeSloth Před 2 lety +2

    Keep up the good work man. I'm re-learning math and got curious about why this works, and I got to understand it from your video.

  • @dajaco81
    @dajaco81 Před 4 lety +11

    This is scary. I was just working out how to define this same formula using integration and I look over at my phone and this video is at the top of my recommended feed 🤯😱

    • @neeeeeck9005
      @neeeeeck9005 Před 4 lety +2

      Well, that'd happen to one person out of so far 251k math students watching this video. Nothing scary, just probability :)

  • @maynorsolischaves2135
    @maynorsolischaves2135 Před 4 lety +3

    Thank you, very helpfull to understand the concept of integral, any chance to generate a similar video related to a sphere? using the same approach

  • @gautamconsultancy6892
    @gautamconsultancy6892 Před 4 lety

    really superb......... please continue to make some more. i cant find many more from u in Utube..

  • @pauldoesitall
    @pauldoesitall Před 4 lety

    Beautifully done. Visuals were super helpful thank you

  • @NicotheMerchant
    @NicotheMerchant Před 11 lety +1

    I love this! Excellent explanation and walkthrough of the proof. :)

  • @striking_village
    @striking_village Před 5 lety

    First time I understand how their multiple of 1/3 came thank you out soooooooooooomuch

  • @WirelessG
    @WirelessG Před rokem

    Great video for anyone. Thank you very much for making this!!!

  • @SabrinaXe
    @SabrinaXe Před 5 lety +1

    That was a very concise video, thanks!

  • @backyard282
    @backyard282 Před 7 lety +25

    What an amazing video with marvelous explanations! Thanks a lot!

  • @TamNguyen-yk9mn
    @TamNguyen-yk9mn Před 4 lety

    I'm confuse as to how and why he divided the length of the base by the high of the pyramid to get the length of each slice base. Can someone explain?

  • @Hellfuryfire666
    @Hellfuryfire666 Před 4 lety

    Good video, everything very clear, however I have a question. What if the base of the pyramid was not rectangular? How could you get the formula for your volume?

  • @nathanbeer3338
    @nathanbeer3338 Před 6 lety +5

    Thank you very much for the proof! My math teacher said that whoever will lecture the proof the volume of the pyramid to the class will earn 5 points more on the upcoming exam.

  • @galanoth17
    @galanoth17 Před 9 lety +5

    Wow this is amazing. Like seriously. Brilliantly simple. The visualizations aid soo much. This could've saved me hours of pondering in school.

  • @hayes.
    @hayes. Před 5 lety

    thanks a lot! this really helped me understand, I kinda really didn't get the point... amazing explanations

  • @aarjith2580
    @aarjith2580 Před 2 lety +1

    *I HAVE A DOUBT!* Can anyone prove why the volume of a pyramid does not depend on the position of the top vertex when it is placed in a plane parallel to the base and only on the height of the top vertex and the base area?

  • @Iwisheyeknew
    @Iwisheyeknew Před 10 lety +2

    Beautifully done.

  • @xdragon2k
    @xdragon2k Před rokem

    I assume this works with any shape base that focused with straight line to one point at the top.

  • @fatimakeyr9813
    @fatimakeyr9813 Před 6 lety

    Very nice video with a clear explanation.
    Can I suggest that rather than writing the (prism #) as ‘n’ you give it another letter instead? This confused me a little as in 04:45 I thought... couldn’t you just cancel the n’s in (n*L/n)^2 ?
    It took me a little while to figure out the ‘n’ you gave for the prism # is different to the ‘n’ in the number of slices.

  • @brandonklein1
    @brandonklein1 Před 6 lety

    So, this is a wonderful way of deriving this, I was curious about this before watching the video and thought that taking an integral of the area of a square l^2 dl giving (l^3)/3, why is this approach incorrect?

  • @MirrorNeuron
    @MirrorNeuron Před rokem

    how long did it take to create this video? I am interested in creating similar videos.

  • @Nulono
    @Nulono Před 4 lety

    Your link to the sum of squares video isn't there.

  • @sergiosutti4675
    @sergiosutti4675 Před 4 lety +2

    Just use calculus. One simple integration of a constant and you get the formula

    • @roberthorwat6747
      @roberthorwat6747 Před 4 lety +2

      Calculus!!!!???????
      Sir! Do you want to see flames shoot out my ears! We don't need no stinkin' calculus⚡💥💣💥

  • @chenadam6339
    @chenadam6339 Před 6 lety

    thank you very much it explains everything i was stuck at!!!

  • @MrDynamite110
    @MrDynamite110 Před 11 lety

    There is no link in the description! :(

  • @hannakim361
    @hannakim361 Před 9 lety +1

    This was so helpful but oh my goodness this is so much work

    • @roberthorwat6747
      @roberthorwat6747 Před 4 lety +1

      ...but good to know the understanding is not beyond your reach. I was taught this formula in the mid 1970's and felt cheated there was no proof given. 50 years later and I can die happy knowing I can actually follow the proof. This is GOLD!!!

  • @asinguadj8530
    @asinguadj8530 Před rokem

    may I ask on 6:18 part why did they exchange the denominator? thank u

  • @alanckh468
    @alanckh468 Před 7 lety +5

    This is a nice video !
    What software did you use to make these animation?

  • @gaemer3967
    @gaemer3967 Před 4 lety +1

    finally, a detailed explanation.

  • @IzchakovDavid
    @IzchakovDavid Před 10 lety

    Cool explanation man!

  • @sonekapanchi6457
    @sonekapanchi6457 Před 3 lety

    From stepsis to step pyramid what a journey I cleared

  • @bloxio3001
    @bloxio3001 Před 4 lety

    Great video...I really enjoyed thanks :)... Though I got to point one mistake in it... On minute 7:10... It is said that "as it approaches infinity the number becomes so small that it actually becomes equal to 0..."... that's actually not possible as infinity is not a integer but a concept and Maths says that it is not possible to divide by 0 out infinity... They both are concepts used in limits where we get the number to be so small that we actually take it as a 0 but it will never be a true 0, it will be 0.000....001. That's the way we use to know what happens when we deal with infinity... Anyway it has been a great video that fascinated me and I only wanted to point that out... Thanks for the vid :)

  • @vivekvishalchoudhary8122

    Very good amazing explanation

  • @tearchi
    @tearchi Před 5 lety +2

    Your videos are awesome and very informative and are on a different level from most explanations, Thank You.

  • @MrOfstring
    @MrOfstring Před 4 lety +4

    They give us formulas and make us solve hundreds of equations and problems as a torture, and they completely miss all the interesting stuff. Wish I had better teachers back then

    • @highguardian13
      @highguardian13 Před 4 lety

      MrOfstring ikr they dont give a damn

    • @boktampu
      @boktampu Před 4 lety

      Are you really could understand this at 6th grade...? Really?

    • @MuitaMerdaAoVivo
      @MuitaMerdaAoVivo Před 4 lety

      This is calculus 1 mate, what he did was just an overcomplicated integral.

    • @MrOfstring
      @MrOfstring Před 4 lety

      @@boktampu if they're intelligent enough to use formulas in appropriate contexts they should be smart enough to grasp the basic logic behind how we came up with these formulas

  • @igorturturro9142
    @igorturturro9142 Před 5 lety

    Great Explanation!

  • @estudante5122
    @estudante5122 Před rokem

    Awesome video!

  • @skylerluu703
    @skylerluu703 Před 10 lety

    NICE,IT HELP ON MY STATE EXAM,THANKS! :)

  • @chrisraeburn9015
    @chrisraeburn9015 Před 6 lety

    This is an excellent video.

  • @altinoveigafilho3266
    @altinoveigafilho3266 Před 4 lety

    Excelente dedução . Parabéns

  • @Deepak-pi9xx
    @Deepak-pi9xx Před 7 lety +1

    Thank you, you saved my time

  • @mueletech
    @mueletech Před 2 měsíci

    I am late , but why did u divide the triangle 😢, i thiught each strip is lomger than the other by 2L/n not by L/n

  • @jannuellaurodizon3016
    @jannuellaurodizon3016 Před 7 lety

    I don't understand why you transfer 6 with n^2

  • @LChaoticrender
    @LChaoticrender Před 3 lety

    Woooow. At first I stopped and digested this like nahh whats he talking bout. Had a flash back then I finished the video and 💥💥💥boom it all made sense! 👏😮

  • @c0wpredator
    @c0wpredator Před 8 lety +2

    Why did you divide the number of slices of the length the same was as the height?

    • @ripperfisher182250
      @ripperfisher182250 Před 8 lety

      well n represents numbers. so the the n became representative of all numbers. remember the goal is to infinitely deivide them. so you can't place a number there. so you go ahead and set up a method where you can lim n>infinity. so you can remove all n's

  • @Philosophy520
    @Philosophy520 Před 11 lety

    Is there a special class that teaches this? If your using a book, what book shows this?

  • @desmundloo3917
    @desmundloo3917 Před 4 lety

    Excellent Stuff!

  • @5abdoabdo
    @5abdoabdo Před 10 lety +9

    wonderful!! Keep going bro

  • @apolllos7
    @apolllos7 Před 9 lety

    looking over this again, length = prism # (L/n) only applies when each number prism is twice as long as the next one down. Is this honestly true for all pyramids?

    • @qbwkp
      @qbwkp Před 8 lety

      +Andrew f Here's the general infinite sum that works for an arbitrary base/height. lim(d->∞)"sum as "i" goes from 0 to ∞" (bh/d)(1-i/d)^2. From this we can derive the general formula, bh/3.

  • @vroomie
    @vroomie Před 7 lety +5

    You're my shepherd. I just killed the subscribe button.
    Keep posting.

  • @klaik30
    @klaik30 Před 8 lety

    So in any equation... If i know that n closes to 0 if i increase it to infinity... I can just ignore it?

  • @Saki630
    @Saki630 Před 4 lety +1

    5:25 dont you need a Summation on the left?

  • @muhammadalhasani2841
    @muhammadalhasani2841 Před 7 lety

    amazing explanations

  • @pxorex
    @pxorex Před 10 lety +1

    amazing stuff thank you

  • @gitaglobalschool3218
    @gitaglobalschool3218 Před rokem +1

    When I ask for any proof, My teacher says you have to explore it yourself it is not in the syllabus and just tells the formula directly without any knowldege of the source of the formula

  • @sowrishvijaay7815
    @sowrishvijaay7815 Před 4 lety +1

    Legendary video

  • @someone-ne5bu
    @someone-ne5bu Před 7 měsíci +2

    can someone please explain to me how he switched between the n^2 and 6 at 6:15 ? or if this is an algebraic rule then please let me now its name. and thank you upfront👍

    • @mathematicsonline
      @mathematicsonline  Před 7 měsíci +1

      this is multiplying any fractions: a/b x c/d = ac/bd = a/d x c/b

    • @someone-ne5bu
      @someone-ne5bu Před 7 měsíci +1

      @mathematicsonline oh it's that simple! Thanks, man, and great video, BTW.

  • @woofle4830
    @woofle4830 Před 4 lety

    heigth of the prism?

  • @stuffthings1417
    @stuffthings1417 Před 4 lety +1

    Heigth?

  • @radheshyamkumawat6494
    @radheshyamkumawat6494 Před 2 lety

    which software you have used to make this visually fantastic video...?
    you have given a wonderful explaination.
    please tell me I am also wants to try this to taught structure design to Architectural Students.

  • @mba2ceo
    @mba2ceo Před 7 lety

    Please do one for Triangular Pyramid

  • @janicknorman9396
    @janicknorman9396 Před 9 lety +3

    This is amazing

  • @vortex8711
    @vortex8711 Před rokem

    Why switch denominators???????

  • @juand.morales274
    @juand.morales274 Před 4 lety +1

    Es difícil entender perfectamente lo que dice ya que no hablo muy bien inglés pero aún así entiendo gracias a sus gráficos
    Está excelente

  • @ValidatingUsername
    @ValidatingUsername Před 3 měsíci

    Geometrically if you push the volume up against the wall on the centreline , copy it, flip the copy, line it up on the other side, it makes a rectangle prism and the holes on the sides are 1/2 the volume.
    Proof of this is left to the reader as an exercise.

  • @alexussr3
    @alexussr3 Před 11 lety

    I appreciate you taking your time to explain this on youtube. Good video!

  • @alburnto
    @alburnto Před 4 lety +1

    mind blown. Thanks.

  • @niceguy4801
    @niceguy4801 Před 3 lety

    Thank-you sir!

  • @denvervelasquez5481
    @denvervelasquez5481 Před 7 lety

    Brilliant! Thanks for this. :-)

  • @kevykanga
    @kevykanga Před 10 lety

    Magnificent! I enjoy your pace and thorough explanations!

  • @asheep7797
    @asheep7797 Před 3 lety +1

    1:58
    There are 2 spellings of height on screen, and it is spelt height, and not heigth.

  • @captainobvious7370
    @captainobvious7370 Před 11 lety +1

    Mind blown! But how did the greeks do this? Amazing!

  • @markopetrov6670
    @markopetrov6670 Před 2 lety

    An outstanding proof. Who came up with it?

  • @metroexodus4388
    @metroexodus4388 Před 6 lety

    amazing , thank u so much !

  • @clawsie5543
    @clawsie5543 Před 4 lety

    What is interesting is that you don't even need to calculate the sum of squares in 4:47. That's because we know that sum of polynomial sequence a_n x^n + a_{n - 1} x^{n - 1} ... a_0 of degree n will always result in polynomial of the degree n + 1. That means that the limit is already convergent, as quotient of two polynomials of the same degree always converge when approaching infinity and not only that, but the limit only depends on the coefficient of the highest degree. We also know that an polynomial of degree n can be exactly defined only by n + 1 points (all with different x coordinates). Knowing all that, we can interpolate the sum of squares if we have 4 points (to get polynomial of degree 3), but as we only need coefficient of the highest degree, there is no need to interpolate all polynomial. We can calculate de coefficient of the highest degree very simple, here is an "recursive" algorithm:
    1. Take n + 1 points of polynomial of degree n with different x coordinates.
    2. Take differences of the consecutive terms, forming a new sequence out of them.
    3. Repeat point "2." until there's is only one number.
    4. The coefficient of the highest degree is that number from point "3." divided by n! and divided by the power of n of the interval between consecutive x coordinates ((x_{k + 1} - x_k)^n), assuming that it is constant.
    In our case we have:
    1. Points are (1, 1^2), (2, 1^2 + 2^2), (3, 1^2 + 2^2 + 3^2), (4, 1^2 + 2^2 + 3^2 + 4^2)
    2. The differences would be:
    2^2 + 1^2 - 1^2 = 2^2 = 4 | 3^2 + 2^2 + 1^2 - (2^2 + 1^2) = 3^2 = 9 | (4^2 + 3^2 + 2^2 + 1^2) - (3^2 + 2^2 + 1^2) = 4^2 = 16
    9 - 4 = 5 | 16 - 9 = 7
    7 - 5 = 2
    4. So the coefficient is 2 / (3! 1^3) = 1 / 3 and the first term is 1/3 n^3
    If you do that algorithm with more than n + 1 points, you will see that at certain point you will get sequence of constants. It works because difference between consecutive terms will always eliminate the term of the highest degree, for example, (n + 1)^2 - n^2 = 2n + 1, 2(n + 1) + 1 - (2n + 1) = 2. If you track down how the final value is calculated without simplifications, you will basically get the definition of the n-th derivative. Note that the n-th derivative of polynomial of degree n gives the derivative exactly, no matter what interval you choose. It only works with polynomials, whereas with other functions you get only approximate value.

  • @josepereira2759
    @josepereira2759 Před 4 lety

    this can be applied for any cone

  • @jadneves
    @jadneves Před 4 lety

    Deduzi a série dos quadrados como:
    (1/3)*n^3 + (1/2)*n^2 + (1/6)*n
    e o número de blocos numa pirâmide multiplicando-a por 4:
    (2/3)*(2n^3 + 3n^2 + n)
    mas isso foi num processo totalmente geométrico, ou braçal, retirando-a de dentro de um cubo, tal como numa lapidação, e a “anti-pirâmide”, ou entulho, ou Antimatéria, é:
    (2/3)*(4n^3 - 3n2 - n)
    Onde somando pirâmide e “anti-pirâmide” teremos nosso Cubo quadruplicado.

  • @abz124816
    @abz124816 Před 9 lety +4

    great lesson. this is how you spell height :)

  • @youngmasterzhi
    @youngmasterzhi Před 3 lety +1

    I always thought that the volume of a pyramid was derived from cutting a prism into three pyramids

  • @LuckyChuhan
    @LuckyChuhan Před 9 lety

    Isn't it b^2h\3?

  • @WiperTF2
    @WiperTF2 Před 10 lety

    Great videos

  • @vivekprasad1938
    @vivekprasad1938 Před 7 lety +1

    thank you vvvveeeerrrrryyy vvvveeerrryyy mmmuuuccchhh....genius...

  • @rockyliu2
    @rockyliu2 Před 11 lety

    thanks for the video

  • @rogeronslow1498
    @rogeronslow1498 Před 4 lety

    Why do you call the individual rectangles "prisms"? I thought a prism was a triangular solid.

    • @n0ame1u1
      @n0ame1u1 Před 4 lety

      Nah, rectangular prism is the correct term for a shape like this

  • @FailedNuance
    @FailedNuance Před 8 lety +2

    6:10 How can you get away with switching the denominators?

    • @ktam111696
      @ktam111696 Před 8 lety +5

      +FailedNuance algebra, multiplying can be done in whatever order 2 x 3 = 3 x 2 or in this case, (24/5)(27/6) = (24/6)(27/5)

    • @wesleyfurtado8065
      @wesleyfurtado8065 Před 8 lety

      I couldnt understand. (24/5)(27/6)=4,5 and (24/6)(27/5)=5,4 , right?

    • @ktam111696
      @ktam111696 Před 8 lety +3

      (2/6)(3/5)=6/30=1/5
      (3/6)(2/5)=6/30=1/5

    • @MsMythMysterious
      @MsMythMysterious Před 6 lety

      e.g.
      12/2 x 6/3 = 6 x 2 = 12
      12/3 x 6/2 = 4 x 3 = 12

    • @firstnamelastname-wt2vc
      @firstnamelastname-wt2vc Před 4 lety

      @@wesleyfurtado8065 uuhh, it's 21.6 in both cases

  • @raina_Bhavesh
    @raina_Bhavesh Před 7 lety

    It's nice, but is confusing because you have used the same variable many a time like for no. of prisms, and for the slices, etc.