stevenvh
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 Sep13 comment How do I map a spherical triangle to a plane triangle? Maybe also interesting for gis.stackexchange.com? Sep13 asked Why is $e^{\pi \sqrt{163}}$ almost an integer? Sep13 revised sangaku - a geometrical puzzle deleted 59 characters in body Sep13 comment sangaku - a geometrical puzzle This is the approach I followed too, but I had some trouble finding a second equation to get rid of the theta :-( Sep13 comment sangaku - a geometrical puzzle accepted as answer for indeed looking nicer than your other solution. Sep13 accepted sangaku - a geometrical puzzle Sep12 revised sangaku - a geometrical puzzle edited title; added 15 characters in body Sep12 revised sangaku - a geometrical puzzle added 79 characters in body Sep12 asked sangaku - a geometrical puzzle Sep12 revised Boy Born on a Tuesday - is it just a language trick? added 12 characters in body Sep12 comment Boy Born on a Tuesday - is it just a language trick? @muad: there doesn't seem a mistake in your derivation; the error was in my intuition that the day couldn't possibly have anything to do with it. Sep12 revised Boy Born on a Tuesday - is it just a language trick? added 209 characters in body Sep11 comment Do complex numbers really exist? "When you first hear this, it sounds crazy." I must say, when I first saw it being drawn in the Argand plane, it made perfectly sense to me: you introduce an imaginary axis because your imaginary number obviously can fit nowhere on the real axis. If you say i = 1 rotated CW over 90°, then i*i = 1 rotated over 2*90°, and you've arrived at -1, back on the real axis! The Argand plane made it all clear to me. Unfortunately I have no such representation for quaternions :-( Sep11 answered Do complex numbers really exist? Sep11 comment Liouville's number revisited I guess I should have said "Liouville's constant" instead of "Liouville's number". Sep11 revised Boy Born on a Tuesday - is it just a language trick? added 154 characters in body Sep11 answered Boy Born on a Tuesday - is it just a language trick? Sep8 comment We can divide $7^{17} - 7^{15}$ by? I hope this was a multiple choice question, because 6 is not the only answer. There's 1, 2, 3, 4, 6, 7, 8, 12, etcetera. 160 divisors in all :-) Sep8 comment We can divide $7^{17} - 7^{15}$ by? 7^17 - 7^15 = 7^2 * 7^15 - 1 * 7^15 = (7^2 - 1) * 7^15 Sep8 comment We can divide $7^{17} - 7^{15}$ by? 7^17 - 7^15 = (7^2 - 1) * 7^15 = (49 - 1) * 7^15 = 48 * 7^15. No division required.