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Alan and Marcus Go Forth and Multiply

Ratings: 8.00/10 from 1 users.

Alan and Marcus Go Forth and MultiplyEver since he was at school, actor and comedian Alan Davies has hated maths. And like many people, he is not much good at it either. But Alan has always had a sneaking suspicion that he was missing out.

So, with the help of top mathematician Professor Marcus du Sautoy (The Story of Maths and How Long Is A Piece Of String?) Alan is going to embark on a maths odyssey.

Together they visit the fourth dimension, cross the universe and explore the concept of infinity. Along the way, Alan does battle with some of the toughest maths questions of our age.

But did his abilities peak 25 years ago when he got his grade C O-Level? In this documentary, Alan will try to master the most complex maths concept there is.

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21 Comments / User Reviews

  1. Cody Freeman

    I think that's wrong, it is a little hard to grasp until you do the math, but it explains it pretty nicely in the video; I think it's best explained in chart form:

    Pick and Stick Strategy: Pick and Change Strategy:

    Stick Circumstance 1: Change Circumstance 1:
    Unknowingly pick goat, Unknowingly pick goat,
    cow is shown, cow is shown,
    stick with it, change your mind,
    get goat. get car.

    Stick Circumstance 2: Change Circumstance 2:
    Unknowingly pick cow, Unknowingly pick cow,
    goat is shown, goat is shown,
    stick with it, change your mind,
    get cow. get car.

    Stick Circumstance 3: Change Circumstance 3:
    Unknowingly pick car, Unknowingly pick car,
    goat or cow are shown, goat or cow are shown,
    stick with it, change your mind,
    get car. get cow or goat.

    Consider them all and do the math. if you Change your mind, your chances of being right double; If you were to change the rules of the game, this wouldn't apply anymore.

  2. tariqxl

    your original odds are 2/3 in being wrong so chances are you are wrong. By revealing 1 wrong option your odds remain that you are still wrong by 1/2. By giving you the chance to change your mind you are effectively subracting 1/2 from 2/3 giving you odds of 1/1 of being right. I think thats how it works took me AND my sis an agonising 20 mins to figure that out. I now officially hate maths lol

  3. Eugler

    Nice doc. I was hoping for some more actual numbers to see how much of my mathematical understanding was lost since highschool. Still nice doc.
    Can anybody here explain to me why the trick with the cups works? I didn't get it.

  4. coyote03

    amazing documentary, incredibly interesting! Both Alan and Marcus are very engaging!

  5. Epicurean_Logic

    I said

    'a good appreciation of what maths really is.'

    Noone really has an answer to that! If you want to bamboozle a maths proffesor just ask the above statement as a question. i.e what is maths? Expect alot of head scratching and gurning (pulling funny faces). Everyone of them will have a different explanation and none will be the complete answer.

    i meant, a good well rounded appreciation of maths.

  6. Epicurean_Logic

    @pamela, when you said

    'this documentary helps me to see where my schooling made me not see the importance of mathematics'

    you are expressing a common feeling about the subject that many people can relate to; namely that there is too much detail and not enough of the bigger picture in school level maths. Its not an easy problem to adress because of the massive size of the subject and consequently the large amount of study of the 'details' that is required. It is however fair to say that both the details and the bigger picture are required for a good apprciation of what maths really is.

    i laughed when you wrote

    'they were teaching it like making a pot of soup.'

    for the reason that maths theorems are very much like a recipe for making soup. you follow the instruction, check the ingredients, and hopefully get the desired result. So it was an insightful comment made in jest. maybe you do have some talent for the subject after all!

  7. Marco Slot


    First, I think the donut is more of a matter of mathematical elegance than proper physics. There is little astronomical evidence that suggests the universe is cyclical.

    Second, we don't really know. There might be something the universe is effectively in, similar to the way our universe contains smaller worlds. This may go on forever if our universe is some sort of infinite fractal. "It's turtles all the way down". At this point, we have no way of figuring this out. Although, among theoretical physicist, there is a suspicion of parallel universes (many worlds theory) floating in dimensions of space that are not readily accessible from our universe (m-theory).

    Third, you should think in terms of mathematical concepts and relationships, things that are true regardless of space and time. Something like the relationship 12+12=24. The main thing is to be able to put all your human intuition aside. We already known the universe at the quantum level is nothing like what we normally encounter. What we see as the rules of physics, break down into rules of information. Particles can be at multiple places at the same time, can change into other particles, merge or split, can appear and disappear, have inverses (anti-particles), anything that can happen to them does happen, they don't have a size or specific position and are not strictly bound by space or time. Very much unlike physical objects as we intuitively know them, but much like little bits of information.

    Seeing the universe with all its space, time, particles, waves and motion as a mathematical information structure, your question ends up being similar to: What are the natural numbers (1,2,3,...) floating in?

    You might say that question doesn't make any sense, but it does touch upon the philosophical side of maths. One may consider, why are there natural numbers at all? What is it about the universe that we were able to discover them and their relationships? Why is there apparently more structure to the universe than none at all? Wouldn't the truly natural state for the universe to be in be nothing? Could you even say there is "something" or is what we're seeing just some kind of abstract, mathematical structure that inherently exists? Perhaps, for some reason, any structure that could exist does exist, and the existence of our universe and all the others is inevitable.

    Then where does structure come from? Can it arise from nothing? You might consider the universe as an infinite amount of nothing (no nothing would be a contradiction), which gives the universe a little structure (0, infinity). From which, perhaps, all other structure could arise. I'm not doing calculations here, just trying to imagine what an answer might look like. Given the way our brains are wired it will remain extremely hard to connect the abstract and the 'physical'. I like Stephen Wolfram's idea of using computers to search for mathematical structures that look like a developing universe. We may have some fairly satisfactory new insights during our lifetimes.

  8. ohh

    @hmm: This only applies more to a finite universe (steady state theory), one which does not expand. However I think it works with the infinite (big bang) as well, the donut depth will just increase.

  9. pamela

    this documentary helps me to see where my schooling made me not see the importance of mathematics...they were teaching it like making a pot of soup.

  10. Karen

    What is the donut floating in?

  11. Mia Nony

    Jeesh! And to think that I thought, from the lead line, that this was an article about Alan and Marcus as a gay couple trying to have children in a gay marriage!

  12. hmm

    4d donut ??? how do you create that by big bang .. doesn't fit together ,or does it ?

  13. Xavier L.

    You can find it here... It's called " How Long is A Piece of String"

  14. Caroline Harris

    Oh? What is his other documentary?

  15. Xavier L.

    Awesome Doc. Enjoyed both Alan Davies' docs.

  16. WaDe

    i love alan, but this doc was boooooring :P

  17. Achems Razor

    Well it ain't sexy to me, I'm not a chick.

    Otherwise a good doc.

  18. Joe

    Arsenal is clearly not the greatest football club ever, that my friends is Everton FC, the People's Club.

  19. Caroline Harris

    A sexy documnentary. I've off outside to see if I can see myself as I used to be!

  20. Tara

    I knew he was in another documentary :) ! Love it