Recent content by nikkor180

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    I Space-time curvature and the fabric of space

    Greetings: I watched several videos describing so-called "empty space" as being permeated with fields (electron field, quark field, etc.). Is it possible that it is actually these fields that curve about large masses and that the trajectory of light and matter curve because they follow the...
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    Einstein's Definition of Mass: m = E/c^2

    Greetings: I hope I am posting in the appropriate forum. I understand that in special relativity, Einstein expressed e = mc^2 as m = e/c^2. Is this his way of defining mass? If not, can you explain how he came to this conclusion?
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    I Gravity in General Relativity: Explaining Acceleration

    Greetings: I can understand that an object's trajectory curves about a greater mass (e. g., satellite in Earth's orbit). The spacetime is curved via the great mass and the moving object simply follows the curvature. My problem is this: Why does a stationary object at a short distance from...
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    MHB Using "calculus" in a sentence

    Deveno: Thank you so much for responding to my post. That was quite a nice dissertation! Best wishes, Rich
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    MHB Using "calculus" in a sentence

    In English grammar, we typically refer to specific branches of mathematics without a prefixed article; e.g., solve using algebra, trig., etc.. By contrast, we often prefix calculus with the definite article, "the". For instance, "solve via the calculus". Can anyone explain this exception to...
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    MHB Proving No Set Contains All Sets Without Russell's Paradox

    Evgeny.Makarov: Thank you for responding to my post. 1) I mean "S is an element of S" (not subset). Regarding "If X is in S for some X not=S, then S - S cannot be empty", I need to ponder that further. I will respond soon. Thanks again, Rich B. BTW, can you tell me how to access symbols...
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    MHB Proving No Set Contains All Sets Without Russell's Paradox

    Greetings: I am attempting to prove that no set contains all sets without Russell's paradox. What I have thus far is this: Let S be an arbitrary set and suppose S contains S. If X is in S for some X not=S, then S - S cannot be empty. But this is a contradiction; hence if S contains S, then...
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    Integration [ 1/(c+cos(x)) ] by dx

    Greetings: If you let u = tan(x/2), then dx = 2*du /(u^2+1), sin(x) = 2u/(u^2+1), cos(x) = (1-u^2)/(1+u^2). If you substitute these values appropriately, each integral should return an inverse trig function. Regards, Rich B.
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    Quick question about integral of (1/x)

    Greetings: d/dx [ln(x)] = lim(h-->0) [(ln(x+h) - ln(x)) / h] = lim(h-->0) [(1/h)*ln[(x+h)/x] = (1/x) lim(h-->0) [(x/h) ln(1+h/x)] = (1/x) lim(h-->0) [ln(1+h/x)^(x/h)] = (1/x) ln [lim(h-->0) [(1+(h/x))^(x/h)]] {from lim[f(g(x))] = f(lim[g(x)])} = (1/x) ln e = 1/x. Since...
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    Gravity: Point where Earth's Gravity and the Moon's cancel each other out?

    Greetings: I believe the point of interest to be none other than the center of mass which is at mer / (me + mm) meters from the Earth along the ray extending from Earth through the moon. Regards, Rich B. rmath4u2@aol.com
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    HW Question, very simple. mass/gravity

    Greetings: If acceleration due to gravity is equal for both the Earth and another planet, then, Gme / re2 = Gmp / rp2. ==> me = (re / rp)2 mp ==> me = (2rp / rp)2 (given re = 2rp) ==> me = 4mp Regards, Rich B. rmath4u2@aol.com
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    Evaluating Limit: x to Infinity

    Greetings: The previous poster was indeed correct in that the numerator's second term goes to zero. That said, the limit becomes, limit(x-->inf) [(ln(1 + 1/sqrt(2))^x) / x]. From the property log(u^n) = n*log(u), we have, limit [x*ln(1 + 1/sqrt(2)) / x] = limit [ln(1 + 1/sqrt(2))] =...
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