Recent content by Von Neumann

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    High School Justification of addition in Spivak, Ch.1

    Yes! Those seem to be the steps I was performing implicitly in going directly from $$x + 3 = 5$$ to $$ x + 3 + 0 = 5$$ I think the prologue of the text will make a lot more sense with this information. Thanks for responding!
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    High School Justification of addition in Spivak, Ch.1

    This is exactly my question! I think I need to get better at formulating exactly what I have a problem understanding. Your response makes sense. I was worried about overthinking this aspect.
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    High School Justification of addition in Spivak, Ch.1

    Yes. Can you be more specific how we can prove this from the three properties listed?
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    High School Justification of addition in Spivak, Ch.1

    I am 100% reading too much into this, but I am curious which of the properties provided by Spivak allow one to justify a specific argument. For reference/context, the properties are: P1: If a, b, and c are any numbers, then $$a +(b + c) = (a + b) +c$$ P2: If a is any number, then $$a + 0 = 0 +...
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    Deriving a conservation law using the divergence theorem

    Like OF said, needs to be radost per unit volume.
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    High School What is the Meaning of ##:=## in Mathematics?

    Thanks fellas!
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    High School What is the Meaning of ##:=## in Mathematics?

    My calc professor always used to use the symbol ##:=## when defining a quantity. For example, say we want to evaluate the integral ## \int x \sqrt{1+x^2} dx ##. So we might say, "Let ##u:=1+x^2 ##" and then continue to easily evaluate the integral. I haven't seen this anywhere else and I'm...
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    Graduate Has the Proton:Electron Mass Ratio Been Solved Yet?

    Reading my old copy (3rd edition) of H&R's Fundamentals of Physics and it states that no theory can predict the value of the proton:electron mass ratio to date, and that it's a "sure-fire" Nobel Prize problem. Has this been resolved yet? Can't find anything on the web. Thanks in advance.
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    Who Are Some Scientists Who Achieved Success Later in Life?

    Of course, Witten is a legend! I thought he was in economics first though.
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    Is HonorSociety.org a Legitimate Organization?

    Thanks for rubbing it in, Phizkid.
  11. V

    Is HonorSociety.org a Legitimate Organization?

    I always appreciate how nice everyone is on PF. :smile:
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    High School Why Is Total Mass Used as the Denominator in the Center of Mass Equation?

    Simply put, it's a weighted average.
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    Is HonorSociety.org a Legitimate Organization?

    Yeah, I was just double-checking. Thanks Astronuc. Indeed. I was proud/flattered before I realized it was a hoax. Oh well.
  14. V

    Is HonorSociety.org a Legitimate Organization?

    Sounds like I should probably just ignore it. Thanks guys.
  15. V

    Is HonorSociety.org a Legitimate Organization?

    Anyone every hear of HonorSociety.org? I recently got an email saying I was accepted into the society via a nomination & my academic record. It's asking for info & I'd like to know it's legitimate before I fill it out. Here's a link to their site: www.honorsociety.org