Recent content by Warp

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    I Infinite flow with capillary tubes?

    I was watching this YouTube video by the channel The Action Lab: At one point it shows this capillary tube phenomenon: It got me immediately thinking: Conservation of energy much? What's stopping that second tube from being bent into draining into the leftmost tube, thus creating an...
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    I A way to comprehend the geometry of a hypercube

    It's extremely hard, if not outright impossible, for our limited brain to visualize 4D objects. 3D objects are fine, but 4D is just impossible (except, maybe, to some people). However, at one point I figured out a way to comprehend (in some ways "visualize") the 4-dimensional hypercube, which...
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    I Melting point of graphite and diamond?

    I was conversing with ChatGPT when I asked which material has the highest melting point, and it answered "tungsten" (giving its melting temperature). It so happened that in the previous question the melting point of graphite had come up, and it was listed as higher than that. When I asked which...
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    B Is the Earth's gravitational pull constant?

    When talking about this subject, terminology tends to be mixed up quite a lot, and the colloquial use of words tends to vary wildly from their strict physics-mathematical definitions. If someone says "gravitational pull is constant" you really have to ask for clarification of what exactly they...
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    I Is there a "smallest" infinite subset of the naturals?

    From an intuitive point of view, an infinite set that's "smaller than the set of natural numbers" would have to be "less than countable". It's hard to imagine what "less than countable infinity" would even mean. How would you even define such a thing? I don't think it can logically be defined.
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    B Alpha Centauri Orbits to Scale?

    I sometimes get surprised by things that do not seem to exist in this world. For example, as far as I know, nobody has ever, during the entire history of photography, made a photographic time-lapse of lunar libration. There are plenty of computer renderings, but no photographic time-lapse...
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    B Monty Hall Paradox: Why Does It Matter What Host Knows?

    Thinking about it, I think I get it. For starters, while it might at first feel that what the host knows and how he acts has no effect (on the rounds where the contestant has a choice), and the only thing that matters is the current door situation at hand, that's actually not true, which...
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    B Monty Hall Paradox: Why Does It Matter What Host Knows?

    That's if the host knowingly opened only goat doors, explicitly avoiding the car door. But suppose that the host opens 98 doors at random (without knowing what's behind them), and it just so happens that this time he opened only goat doors. Very unintuitively, and paradoxically (at least...
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    B Monty Hall Paradox: Why Does It Matter What Host Knows?

    Suppose you are participating in a game show, and at one point three doors are presented. It's announced that one of them has a car prize behind it and the other two have a goat, and for you to choose one of the doors. After choosing the host opens one of the other doors and reveals a goat, and...
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    B Lunar libration time lapse with real photographs?

    I have been trying to find a time lapse animation showing lunar libration made of actual real photographs of the Moon. However, no matter how much I search, I can only find computer-rendered animations. Does anybody know of a video made out of actual photographs of the real thing?
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    Why are structs used for linked lists and classes used for binary trees?

    I mean that (non-virtual) struct member functions do not affect the layout, the bit representation, of the struct, and thus such structs can be used to interface with C libraries (and any other languages that handle such constructs).
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    Why are structs used for linked lists and classes used for binary trees?

    As mentioned, if the struct (or class) is of a "POD type", then it's fully compatible with C (and any other language that may use the same construct). A POD struct can have member functions as long as they aren't virtual. The only types of member functions that aren't allowed are (as mentioned)...
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    Why are structs used for linked lists and classes used for binary trees?

    On a related note, the standard does define the concept of a POD ("Plain Old Data") type, which probably matches the closest to what you originally learned. A POD type is either a scalar type or a struct/class (or union) that's an aggregate type with only POD types as members, no reference...
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    B Extending the Fundamental Theorem of Arithmetic to the rationals

    I have been thinking that it's probably quite easy to show that the factorization is unique. The only way that two rational numbers can be equal is if the numerator and denominator of one are multiples of the numerator and denominator of the other, using the same factor. In other words, $$\frac...
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    B Extending the Fundamental Theorem of Arithmetic to the rationals

    All integers are rational numbers (they belong to ##\mathbb{Q}##). All the prime numbers are integers. Therefore all prime numbers are rational. By saying that prime numbers are not rational you are saying that they are irrational numbers. Does your definition of ##\mathbb{Q}## not include the...
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