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:Reference desk/Archives/Mathematics/2007 July 11 - Knowledge

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324:. One fine point (of many): taking the distant stars as a fixed reference, the time for one complete spin is not the same as the time between sun facings (noons), and the latter varies depending on position in orbit. Again, in this case, the difference is small. Although Earth's orbit is nearly a perfect circle, so the distance to the Sun is nearly constant, the Earth's axis of spin is tilted with respect to the plane of the orbit; thus we have seasons. 1947: 153:
By "summer", I assume you're talking about "natural" or climatic summer, as opposed to official summer. In my country, we're now in winter, which is officially defined as the period 1 June-31 August. This roughly coincides with the natural winter - the times when it's cold, rainy, snowy, foggy etc
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every 400 years. If we didn't have them, today's date 11 July for example, which currently occurs in winter in the southern hemisphere, would progressively occur earlier and earlier. It would at some stage fall in autumn, then in summer, then in spring, then back to winter, and so on. It would
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Ah, when we have an expression like this, which is only meaningful in a certain region, but can be analytically continued to form the function we really want, doesn't it feel like we (mankind) are missing something? It's like our concepts and notation can only reach a very small part of all the
1279:, and other tricks might be able to eliminate other terms as well, but you will almost always end up with an essentially difficult equation. In this particular example, you were lucky enough to have one of the roots equal to the average of the other two, simplifying the equation for 2271: 327:
Sunlight is a major factor in human activity; so is temperature, and so are other seasonal variations. In today's world, when so few people in the developed world engage in agriculture, it is hard to appreciate the critical importance of calendars to
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In the interest of historical accuracy, I would just like to point out that (a) the Gregorian calendar was not adopted at a single date - Spain and Portugal adopted it first in 1582; Great Britain in 1752; Greece did not adopt it until 1923; (b) the
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As for daylight hours - those depend, of course, on the time of solar year and not on our calendars. So the longest day will still be in the beginning of summer, but it won't be the middle of June but a different calendar day every time. --
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Many different sources, including wikipedia, state that the riemann zeta function have trivial zeroes at negative integers. However, this argument states that at the negative even integers, (in the example, s=-2,) the function diverges.
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mathematical object out there, and some only if we bend over backward like in this case. Like we are a one-dimensional creature, living on a string, beginning to suspect that that is not all, there must be more dimensions out there! β€”
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We empirically discover that the length of a day and the length of a year and the length of a month exhibit no exact simple numeric relationships. However, a year (suitably defined) contains 365 days (suitably defined)
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The short version is: Every rational root of a polynomial (with integer coefficients, of course) can be expressed as a divisor of the free term divided by a divisor of the leading term (the coefficient of
308:, again completing each orbit with almost no timing variation from the one before. In this case, these two periods are β€” for most practical purposes β€” not only constant but independent. Not so with the 1146: 202:
That's easy. From 1582 to today there have been 106 years which are multiples of 4. Among these, 1700, 1800 and 1900 are not leap years. So we would be 103 days ahead of today, which is October 18. --
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it would still be mid-winter. To correct this, the official start and end dates of the seasons would need to be moved one further day ahead every year that would otherwise have been a leap year. --
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I have been wondering for quite some time- what would happen if we did not observe leap years? Would our whole calendar just get one day ahead every four years? Would it affect our daylight hours?
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Indeed I was being Mr. Sad & Pedantic - I just didn't want anyone to walk away from the RDs with the misguided impression that there were no leap years before the 16th century.
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in your above explanation you mentioned 'other tricks' for eliminating other terms of a polynomial. Could you expand on 'other tricks' or show me where to find out about them?
599: 1679: 830: 1620: 1724: 1397: 1326: 672: 633: 1243: 1942:{\displaystyle \zeta {(-2)}=\sum _{n=1}^{\infty }{\frac {1}{n^{-2}}}=\sum _{n=1}^{\infty }n^{2}=1+4+9+16+25+36...={\frac {\infty (\infty +1)(2\infty +1)}{6}}=\infty } 1495: 984: 1352: 1277: 952: 932: 336:. That fraction is our problem. What exactly is it, and how do we accomodate it? And, as requested, what happens if we ignore it? The fraction is almost exactly ⁄ 25: 367:
to be in the Spring, but over hundreds of years the drift in the calendar became too much to ignore. So the church dictated a new calendar. Not surprisingly,
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The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the
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Note that the Muslim calendar is purely lunar with no adjustments to bring it into sync with the solar year, so their dates rotate through the seasons.
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For the record, I was thinking about mentioning those points, but ultimately concluded that they aren't relevant for the question or the answer. --
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When I say this I suppose I really mean could you solve something relatively large, say n=9 by constantly applying the appropriate substitution?
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factor in there plus the fact that no other factors are unbounded (which is why you don't have trivial zeroes at nonnegative even integers).
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But it's much easier to see that there are trivial zeros of the zeta function at negative even values from the functional equation, with that
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Now someone who REALLY likes math figure out exactly what time of the year it would be if there were no leap years starting from the time the
37: 2266:{\displaystyle \zeta (s)={\frac {1}{1-2^{1-s}}}\sum _{n=0}^{\infty }{\frac {1}{2^{n+1}}}\sum _{k=0}^{n}(-1)^{k}{n \choose k}(k+1)^{-s}.} 1534: 21: 239:, which had a leap year every 4 years with no exceptions; (c) if we had stayed with the Julian calendar we would now be 13 days 901:
This last stage obviously confirms that the three solutions are consecutive but gives them as -1,0, and 1, which is incorrect.
1047: 2361: 2352: 2338: 2325: 2278: 2053: 2035: 2017: 1953: 1735: 1555: 1541: 1528: 1510: 1462: 1453: 1429: 1412: 1032: 1023: 1014: 1000: 990: 908: 390: 287: 270: 261: 247: 211: 189: 166: 140: 121: 682: 154:- which is a good thing. However, if the 103-day scenario you worked out below applied, and seasonal designations were 1962: 158:
officially changed, today would now be called 18 October and we'd be calling the season "spring" (officially), but
340:, but a little less. If we ignore it, then a calendar based on days bears no fixed relationship with the seasons. 1216: 2348: 1731: 1524: 1506: 1449: 1408: 257: 207: 136: 86: 17: 1501:
time. In your example, all roots are rational, and they are all a divisor of 24 divided by a divisor of 1. --
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that global definition, I just wanted to point out it's there for anyone who dislikes analytic continuation.
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This is indeed an example, but not a particularly useful one as it doesn't give something simpler than
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All timekeeping, not just calendars, must juggle science and commerce and politics and so on. Consider
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I have just discovered Cardano's method for solving cubics and have tested it out, to no avail.
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spins around its axis, and the rate at which is does so is fairly constant. It also orbits the
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are a fun topic, involving mathematics, astronomy, agronomy, religion, and politics β€” at least!
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Is this expression not a relatively efficient way of evaluating the function numerically? --
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If you're offering to explain or point me in the right direction then yes, I am interested.
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Here's a substitution to get rid of the linear term in a cubic ax^3 + bx^2 + cx + d = 0
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In case you think this is a major result, it isn't: it's a trivial application of the
937: 917: 1623: 1497:). Since there are only finitely many such divisors, you can find them all in finite 485:
Hence my solutions are obviously 2, 3 and 4 respectively. Expanding this results in
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times? With contributors around the world, we certainly couldn't use local time! --
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I would appreciate someone telling me where I have gone wrong or what to do next.
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were recently a cause for internation debate. Ever notice that Knowledge uses
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take approximately 400*365/97 = 1505 years for the whole cycle to occur. --
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Indeed, that series only defines the zeta function for z with real part : -->
294: 113: 74: 347:, which makes life complicated indeed!) The common Western calendar, the 1253:(roots). The substitution you suggest can eliminate the term of degree 1250: 1019:
That's a big mistake my students made whenever they did substitutions.
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roots of any polynomial, if for any reason those are of interest. --
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1. The function is extended to the complex plane (except 1) by
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th degree cannot be found using only arithmetic operations and
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The sum form of the function is not valid for all values. For
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this should produce a cubic of the form My^3 + Ny^2 + S = 0
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Welcome to the Knowledge Mathematics Reference Desk Archives
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According to the article, Borwein's method is much better.
1141:{\displaystyle x^{n}+a_{1}x^{n-1}+a_{2}x^{n-2}...=0\,\!} 351:, was motivated by an inaccurate use of leap years (the 343:
We cannot ignore religion and politics. (Consider the
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dunno if that's a "trick" you'd want to see or not..
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Of course, there is a general method to find all the
1360: 1334: 1289: 1259: 1225: 1158: 1050: 960: 940: 920: 844: 795: 776:{\displaystyle (t+3)^{3}-9(t+3)^{2}+26(t+3)-24=0\,\!} 685: 644: 610: 568: 494: 416: 676:
Substituting this into the original equation leaves
1283:. Otherwise you would have to solve something like 2313: 2265: 2001: 1941: 1718: 1673: 1614: 1489: 1391: 1346: 1320: 1271: 1237: 1194: 1140: 978: 946: 926: 890: 824: 775: 666: 627: 593: 548: 474: 235:3 leap years in every 400 years from the previous 2229: 2216: 1245:, a solution to a general polynomial equation of 2002:{\displaystyle \zeta (s),s\in \mathbb {Z} ^{-}} 1190: 1136: 886: 820: 771: 662: 623: 544: 470: 8: 1622:. A better example I can suggest appears in 1354:case you might have to solve something like 1006:Hehe, you're welcome. I was a little afraid 231:did not introduce leap years - in fact, it 104:Leap Years - What Would We Do Without Them? 2296: 2288: 2251: 2228: 2215: 2213: 2207: 2188: 2177: 2159: 2150: 2144: 2133: 2114: 2098: 2081: 1993: 1989: 1988: 1964: 1888: 1843: 1833: 1822: 1804: 1795: 1789: 1778: 1757: 1752: 1692: 1686: 1641: 1635: 1585: 1579: 1481: 1475: 1365: 1359: 1333: 1294: 1288: 1258: 1224: 1177: 1171: 1157: 1107: 1097: 1078: 1068: 1055: 1049: 1042:In theory can you solve any polynomial 959: 939: 919: 843: 800: 794: 730: 702: 684: 643: 615: 609: 581: 567: 549:{\displaystyle x^{3}-9x^{2}+26x-24=0\,\!} 515: 499: 493: 415: 49: 36: 2314:{\displaystyle \sin {\frac {\pi s}{2}}} 1195:{\displaystyle x=t-{a_{1} \over n}\,\!} 1188: 1134: 884: 818: 769: 660: 621: 559:Then I have to use the substitution of 542: 468: 65: 359:problems with its yearly major event: 43: 1564:Let x = y + (√(b^2 - 3ac) - 6ac)/3a 475:{\displaystyle (x-2)(x-3)(x-4)=0\,\!} 7: 954:takes the values 2, 3 and 4 because 2330:Sure, only a madman would actually 2220: 2145: 1936: 1915: 1897: 1891: 1834: 1790: 1010:was missing some difficult part. β€” 635:and in this case is therefore -9. 32: 1949:What's wrong with this argument? 1535:fundamental theorem of arithmetic 1328:which is a little harder. In the 996:Wow, is my face red. Many thanks 891:{\displaystyle t(t+1)(t-1)=0\,\!} 1515:Apparently, this is called the 594:{\displaystyle x=t-{a \over 3}} 112:Ultimately, yes. There are 97 2248: 2235: 2204: 2194: 2092: 2086: 1975: 1969: 1924: 1909: 1906: 1894: 1767: 1758: 934:takes the values -1, 0 and 1, 875: 863: 860: 848: 754: 742: 727: 714: 699: 686: 604:where a is the co-efficent of 459: 447: 444: 432: 429: 417: 1: 1674:{\displaystyle x^{5}-5x-4t=0} 825:{\displaystyle t^{3}-t=0\,\!} 33: 1615:{\displaystyle x^{3}+ax+b=0} 1028:Nice to know I'm not alone! 2074:gives a global definition: 1719:{\displaystyle x^{5}+x+a=0} 1392:{\displaystyle t^{5}+t+3=0} 1321:{\displaystyle t^{3}+t+3=0} 1150:by making the substitution 835:Which can then simplify to 407:I start with the equation 2394: 2362:13:42, 12 July 2007 (UTC) 2353:12:55, 12 July 2007 (UTC) 2339:11:36, 12 July 2007 (UTC) 2326:22:11, 11 July 2007 (UTC) 2279:21:02, 11 July 2007 (UTC) 2054:20:36, 11 July 2007 (UTC) 2036:20:17, 11 July 2007 (UTC) 2018:19:02, 11 July 2007 (UTC) 1954:18:51, 11 July 2007 (UTC) 1736:12:37, 12 July 2007 (UTC) 1556:00:09, 12 July 2007 (UTC) 1542:23:10, 11 July 2007 (UTC) 1529:22:09, 11 July 2007 (UTC) 1511:21:51, 11 July 2007 (UTC) 1463:21:47, 11 July 2007 (UTC) 1454:21:43, 11 July 2007 (UTC) 1430:23:22, 11 July 2007 (UTC) 1413:21:40, 11 July 2007 (UTC) 1033:17:55, 11 July 2007 (UTC) 1024:17:51, 11 July 2007 (UTC) 1015:16:22, 11 July 2007 (UTC) 1001:16:20, 11 July 2007 (UTC) 991:16:18, 11 July 2007 (UTC) 909:15:49, 11 July 2007 (UTC) 667:{\displaystyle x=t+3\,\!} 628:{\displaystyle x^{2}\,\!} 391:10:13, 12 July 2007 (UTC) 288:15:29, 11 July 2007 (UTC) 271:14:46, 11 July 2007 (UTC) 262:14:25, 11 July 2007 (UTC) 248:14:17, 11 July 2007 (UTC) 212:13:55, 11 July 2007 (UTC) 190:13:44, 11 July 2007 (UTC) 167:10:43, 12 July 2007 (UTC) 141:13:43, 11 July 2007 (UTC) 122:13:31, 11 July 2007 (UTC) 18:Knowledge:Reference desk 1499:(and I believe polylog) 1421:For quintics there are 1238:{\displaystyle n\geq 5} 2315: 2267: 2193: 2149: 2009:, you need to use the 2003: 1943: 1838: 1794: 1720: 1675: 1616: 1491: 1393: 1348: 1322: 1273: 1239: 1196: 1142: 980: 948: 928: 892: 826: 777: 668: 629: 595: 550: 476: 87:current reference desk 2316: 2268: 2173: 2129: 2072:Riemann zeta function 2029:analytic continuation 2004: 1944: 1818: 1774: 1742:Riemann Zeta Function 1721: 1676: 1617: 1517:rational root theorem 1492: 1490:{\displaystyle x^{n}} 1394: 1349: 1323: 1274: 1240: 1197: 1143: 981: 979:{\displaystyle x=t+3} 949: 929: 893: 827: 778: 669: 638:Substiuting in gives 630: 596: 551: 477: 357:Roman Catholic Church 2287: 2080: 1963: 1751: 1685: 1634: 1578: 1474: 1358: 1332: 1287: 1257: 1223: 1217:Abel–Ruffini theorem 1156: 1048: 958: 938: 918: 842: 793: 786:This simplifies to 683: 642: 608: 566: 492: 414: 376:daylight saving time 371:had their own ideas. 2011:functional equation 1681:, or equivalently, 1630:to one of the form 1347:{\displaystyle n=5} 1272:{\displaystyle n-1} 369:various governments 2311: 2263: 1999: 1939: 1716: 1671: 1612: 1487: 1389: 1344: 1318: 1269: 1235: 1192: 1191: 1189: 1138: 1137: 1135: 976: 944: 924: 888: 887: 885: 822: 821: 819: 773: 772: 770: 664: 663: 661: 625: 624: 622: 591: 546: 545: 543: 472: 471: 469: 349:Gregorian calendar 243:the current date. 229:Gregorian calendar 183:was established -- 181:Gregorian calendar 2309: 2227: 2171: 2127: 1931: 1813: 1186: 947:{\displaystyle x} 927:{\displaystyle t} 589: 334:and a little more 93: 92: 73: 72: 2385: 2320: 2318: 2317: 2312: 2310: 2305: 2297: 2272: 2270: 2269: 2264: 2259: 2258: 2234: 2233: 2232: 2219: 2212: 2211: 2192: 2187: 2172: 2170: 2169: 2151: 2148: 2143: 2128: 2126: 2125: 2124: 2099: 2008: 2006: 2005: 2000: 1998: 1997: 1992: 1948: 1946: 1945: 1940: 1932: 1927: 1889: 1848: 1847: 1837: 1832: 1814: 1812: 1811: 1796: 1793: 1788: 1770: 1725: 1723: 1722: 1717: 1697: 1696: 1680: 1678: 1677: 1672: 1646: 1645: 1628:quintic equation 1621: 1619: 1618: 1613: 1590: 1589: 1496: 1494: 1493: 1488: 1486: 1485: 1398: 1396: 1395: 1390: 1370: 1369: 1353: 1351: 1350: 1345: 1327: 1325: 1324: 1319: 1299: 1298: 1278: 1276: 1275: 1270: 1244: 1242: 1241: 1236: 1219:states that for 1201: 1199: 1198: 1193: 1187: 1182: 1181: 1172: 1147: 1145: 1144: 1139: 1118: 1117: 1102: 1101: 1089: 1088: 1073: 1072: 1060: 1059: 985: 983: 982: 977: 953: 951: 950: 945: 933: 931: 930: 925: 897: 895: 894: 889: 831: 829: 828: 823: 805: 804: 782: 780: 779: 774: 735: 734: 707: 706: 673: 671: 670: 665: 634: 632: 631: 626: 620: 619: 600: 598: 597: 592: 590: 582: 555: 553: 552: 547: 520: 519: 504: 503: 481: 479: 478: 473: 345:Islamic calendar 75: 38:Mathematics desk 34: 2393: 2392: 2388: 2387: 2386: 2384: 2383: 2382: 2298: 2285: 2284: 2247: 2214: 2203: 2155: 2110: 2103: 2078: 2077: 2070:If you prefer, 1987: 1961: 1960: 1890: 1839: 1800: 1749: 1748: 1744: 1688: 1683: 1682: 1637: 1632: 1631: 1581: 1576: 1575: 1477: 1472: 1471: 1361: 1356: 1355: 1330: 1329: 1290: 1285: 1284: 1255: 1254: 1221: 1220: 1173: 1154: 1153: 1103: 1093: 1074: 1064: 1051: 1046: 1045: 956: 955: 936: 935: 916: 915: 840: 839: 796: 791: 790: 726: 698: 681: 680: 640: 639: 611: 606: 605: 564: 563: 511: 495: 490: 489: 412: 411: 399: 353:Julian calendar 339: 237:Julian calendar 188: 106: 101: 30: 29: 28: 12: 11: 5: 2391: 2389: 2381: 2380: 2379: 2378: 2377: 2376: 2375: 2374: 2373: 2372: 2371: 2370: 2369: 2368: 2367: 2366: 2365: 2364: 2345:Meni Rosenfeld 2308: 2304: 2301: 2295: 2292: 2273: 2262: 2257: 2254: 2250: 2246: 2243: 2240: 2237: 2231: 2226: 2223: 2218: 2210: 2206: 2202: 2199: 2196: 2191: 2186: 2183: 2180: 2176: 2168: 2165: 2162: 2158: 2154: 2147: 2142: 2139: 2136: 2132: 2123: 2120: 2117: 2113: 2109: 2106: 2102: 2097: 2094: 2091: 2088: 2085: 2061: 2060: 2059: 2058: 2057: 2056: 2041: 2040: 2039: 2038: 2021: 2020: 1996: 1991: 1986: 1983: 1980: 1977: 1974: 1971: 1968: 1938: 1935: 1930: 1926: 1923: 1920: 1917: 1914: 1911: 1908: 1905: 1902: 1899: 1896: 1893: 1887: 1884: 1881: 1878: 1875: 1872: 1869: 1866: 1863: 1860: 1857: 1854: 1851: 1846: 1842: 1836: 1831: 1828: 1825: 1821: 1817: 1810: 1807: 1803: 1799: 1792: 1787: 1784: 1781: 1777: 1773: 1769: 1766: 1763: 1760: 1756: 1743: 1740: 1739: 1738: 1728:Meni Rosenfeld 1715: 1712: 1709: 1706: 1703: 1700: 1695: 1691: 1670: 1667: 1664: 1661: 1658: 1655: 1652: 1649: 1644: 1640: 1611: 1608: 1605: 1602: 1599: 1596: 1593: 1588: 1584: 1559: 1558: 1549:Meni Rosenfeld 1546: 1545: 1544: 1521:Meni Rosenfeld 1513: 1503:Meni Rosenfeld 1484: 1480: 1467: 1466: 1465: 1446:Meni Rosenfeld 1438: 1437: 1436: 1435: 1434: 1433: 1432: 1423:Bring Radicals 1405:Meni Rosenfeld 1388: 1385: 1382: 1379: 1376: 1373: 1368: 1364: 1343: 1340: 1337: 1317: 1314: 1311: 1308: 1305: 1302: 1297: 1293: 1268: 1265: 1262: 1234: 1231: 1228: 1185: 1180: 1176: 1170: 1167: 1164: 1161: 1133: 1130: 1127: 1124: 1121: 1116: 1113: 1110: 1106: 1100: 1096: 1092: 1087: 1084: 1081: 1077: 1071: 1067: 1063: 1058: 1054: 1040: 1039: 1038: 1037: 1036: 1035: 994: 993: 975: 972: 969: 966: 963: 943: 923: 899: 898: 883: 880: 877: 874: 871: 868: 865: 862: 859: 856: 853: 850: 847: 833: 832: 817: 814: 811: 808: 803: 799: 784: 783: 768: 765: 762: 759: 756: 753: 750: 747: 744: 741: 738: 733: 729: 725: 722: 719: 716: 713: 710: 705: 701: 697: 694: 691: 688: 659: 656: 653: 650: 647: 618: 614: 602: 601: 588: 585: 580: 577: 574: 571: 557: 556: 541: 538: 535: 532: 529: 526: 523: 518: 514: 510: 507: 502: 498: 483: 482: 467: 464: 461: 458: 455: 452: 449: 446: 443: 440: 437: 434: 431: 428: 425: 422: 419: 398: 397:Cubic equation 395: 394: 393: 372: 355:) causing the 341: 337: 329: 325: 316:; not so with 298: 291: 290: 281: 280: 279: 278: 277: 276: 275: 274: 273: 254:Meni Rosenfeld 219: 218: 217: 216: 215: 214: 204:Meni Rosenfeld 195: 194: 193: 192: 184: 174: 173: 172: 171: 170: 169: 146: 145: 144: 143: 133:Meni Rosenfeld 125: 124: 105: 102: 100: 97: 95: 91: 90: 82: 81: 71: 70: 64: 48: 41: 40: 31: 15: 14: 13: 10: 9: 6: 4: 3: 2: 2390: 2363: 2360: 2356: 2355: 2354: 2350: 2346: 2342: 2341: 2340: 2337: 2333: 2329: 2328: 2327: 2324: 2306: 2302: 2299: 2293: 2290: 2282: 2281: 2280: 2277: 2274: 2260: 2255: 2252: 2244: 2241: 2238: 2224: 2221: 2208: 2200: 2197: 2189: 2184: 2181: 2178: 2174: 2166: 2163: 2160: 2156: 2152: 2140: 2137: 2134: 2130: 2121: 2118: 2115: 2111: 2107: 2104: 2100: 2095: 2089: 2083: 2076: 2075: 2073: 2069: 2068: 2067: 2066: 2065: 2064: 2063: 2062: 2055: 2052: 2047: 2046: 2045: 2044: 2043: 2042: 2037: 2034: 2030: 2025: 2024: 2023: 2022: 2019: 2016: 2012: 1994: 1984: 1981: 1978: 1972: 1966: 1958: 1957: 1956: 1955: 1952: 1933: 1928: 1921: 1918: 1912: 1903: 1900: 1885: 1882: 1879: 1876: 1873: 1870: 1867: 1864: 1861: 1858: 1855: 1852: 1849: 1844: 1840: 1829: 1826: 1823: 1819: 1815: 1808: 1805: 1801: 1797: 1785: 1782: 1779: 1775: 1771: 1764: 1761: 1754: 1741: 1737: 1733: 1729: 1713: 1710: 1707: 1704: 1701: 1698: 1693: 1689: 1668: 1665: 1662: 1659: 1656: 1653: 1650: 1647: 1642: 1638: 1629: 1625: 1624:Bring radical 1609: 1606: 1603: 1600: 1597: 1594: 1591: 1586: 1582: 1573: 1572: 1571: 1568: 1565: 1562: 1557: 1554: 1550: 1547: 1543: 1540: 1536: 1532: 1531: 1530: 1526: 1522: 1518: 1514: 1512: 1508: 1504: 1500: 1482: 1478: 1468: 1464: 1461: 1457: 1456: 1455: 1451: 1447: 1443: 1439: 1431: 1428: 1424: 1420: 1419: 1418: 1417: 1416: 1415: 1414: 1410: 1406: 1402: 1386: 1383: 1380: 1377: 1374: 1371: 1366: 1362: 1341: 1338: 1335: 1315: 1312: 1309: 1306: 1303: 1300: 1295: 1291: 1282: 1266: 1263: 1260: 1252: 1248: 1232: 1229: 1226: 1218: 1214: 1210: 1209: 1208: 1207: 1202: 1183: 1178: 1174: 1168: 1165: 1162: 1159: 1151: 1148: 1131: 1128: 1125: 1122: 1119: 1114: 1111: 1108: 1104: 1098: 1094: 1090: 1085: 1082: 1079: 1075: 1069: 1065: 1061: 1056: 1052: 1043: 1034: 1031: 1027: 1026: 1025: 1022: 1018: 1017: 1016: 1013: 1009: 1005: 1004: 1003: 1002: 999: 992: 989: 973: 970: 967: 964: 961: 941: 921: 913: 912: 911: 910: 907: 902: 881: 878: 872: 869: 866: 857: 854: 851: 845: 838: 837: 836: 815: 812: 809: 806: 801: 797: 789: 788: 787: 766: 763: 760: 757: 751: 748: 745: 739: 736: 731: 723: 720: 717: 711: 708: 703: 695: 692: 689: 679: 678: 677: 674: 657: 654: 651: 648: 645: 636: 616: 612: 586: 583: 578: 575: 572: 569: 562: 561: 560: 539: 536: 533: 530: 527: 524: 521: 516: 512: 508: 505: 500: 496: 488: 487: 486: 465: 462: 456: 453: 450: 441: 438: 435: 426: 423: 420: 410: 409: 408: 405: 402: 396: 392: 389: 385: 381: 377: 373: 370: 366: 362: 358: 354: 350: 346: 342: 335: 330: 326: 323: 320:orbiting the 319: 315: 312:orbiting the 311: 307: 303: 299: 296: 293: 292: 289: 286: 282: 272: 269: 265: 264: 263: 259: 255: 251: 250: 249: 246: 242: 238: 234: 230: 225: 224: 223: 222: 221: 220: 213: 209: 205: 201: 200: 199: 198: 197: 196: 191: 187: 182: 178: 177: 176: 175: 168: 165: 161: 157: 152: 151: 150: 149: 148: 147: 142: 138: 134: 129: 128: 127: 126: 123: 120: 115: 111: 110: 109: 103: 98: 96: 88: 84: 83: 80: 77: 76: 68: 61: 57: 53: 47: 42: 39: 35: 27: 23: 19: 2331: 2323:Donald Hosek 2015:Donald Hosek 1745: 1569: 1566: 1563: 1560: 1498: 1441: 1400: 1280: 1246: 1212: 1203: 1152: 1149: 1044: 1041: 1021:Donald Hosek 1007: 995: 903: 900: 834: 785: 675: 637: 603: 558: 484: 406: 403: 400: 380:leap seconds 364: 333: 240: 232: 160:climatically 159: 155: 107: 94: 78: 1553:Algebra man 1460:Algebra man 1403:harder. -- 1206:Algebra man 1030:Algebra man 998:Algebra man 906:Algebra man 26:Mathematics 2359:Algebraist 2336:Algebraist 2276:Algebraist 2051:Bromskloss 2033:Algebraist 1539:Algebraist 1215:fast. The 1012:Bromskloss 988:Bromskloss 986:, right? β€” 295:Leap years 1951:Indeed123 1399:which is 363:. It was 328:survival. 268:Gandalf61 245:Gandalf61 114:leap days 50:<< 1442:rational 1427:Cronholm 1251:radicals 904:Thanks. 365:supposed 285:Gzuckier 164:JackofOz 119:JackofOz 24:‎ | 22:Archives 20:‎ | 318:Mercury 233:removed 99:July 11 89:pages. 67:July 12 46:July 10 361:Easter 241:behind 1883:36... 1726:. -- 1519:. -- 388:KSmrq 314:Earth 302:Earth 69:: --> 63:: --> 62:: --> 44:< 16:< 2349:talk 1732:talk 1525:talk 1507:talk 1450:talk 1409:talk 1401:much 1211:Not 310:Moon 300:The 258:talk 208:talk 137:talk 56:July 2332:use 2291:sin 914:If 384:UTC 322:Sun 306:Sun 156:not 60:Aug 52:Jun 2351:) 2300:Ο€ 2294:⁑ 2253:βˆ’ 2198:βˆ’ 2175:βˆ‘ 2146:∞ 2131:βˆ‘ 2119:βˆ’ 2108:βˆ’ 2084:ΞΆ 2031:. 2013:. 1995:βˆ’ 1985:∈ 1967:ΞΆ 1937:∞ 1916:∞ 1898:∞ 1892:∞ 1877:25 1871:16 1835:∞ 1820:βˆ‘ 1806:βˆ’ 1791:∞ 1776:βˆ‘ 1762:βˆ’ 1755:ΞΆ 1734:) 1657:βˆ’ 1648:βˆ’ 1537:. 1527:) 1509:) 1452:) 1425:-- 1411:) 1264:βˆ’ 1230:β‰₯ 1213:so 1169:βˆ’ 1112:βˆ’ 1083:βˆ’ 870:βˆ’ 807:βˆ’ 761:24 758:βˆ’ 740:26 709:βˆ’ 579:βˆ’ 534:24 531:βˆ’ 525:26 506:βˆ’ 454:βˆ’ 439:βˆ’ 424:βˆ’ 260:) 210:) 139:) 58:| 54:| 2347:( 2307:2 2303:s 2261:. 2256:s 2249:) 2245:1 2242:+ 2239:k 2236:( 2230:) 2225:k 2222:n 2217:( 2209:k 2205:) 2201:1 2195:( 2190:n 2185:0 2182:= 2179:k 2167:1 2164:+ 2161:n 2157:2 2153:1 2141:0 2138:= 2135:n 2122:s 2116:1 2112:2 2105:1 2101:1 2096:= 2093:) 2090:s 2087:( 1990:Z 1982:s 1979:, 1976:) 1973:s 1970:( 1934:= 1929:6 1925:) 1922:1 1919:+ 1913:2 1910:( 1907:) 1904:1 1901:+ 1895:( 1886:= 1880:+ 1874:+ 1868:+ 1865:9 1862:+ 1859:4 1856:+ 1853:1 1850:= 1845:2 1841:n 1830:1 1827:= 1824:n 1816:= 1809:2 1802:n 1798:1 1786:1 1783:= 1780:n 1772:= 1768:) 1765:2 1759:( 1730:( 1714:0 1711:= 1708:a 1705:+ 1702:x 1699:+ 1694:5 1690:x 1669:0 1666:= 1663:t 1660:4 1654:x 1651:5 1643:5 1639:x 1610:0 1607:= 1604:b 1601:+ 1598:x 1595:a 1592:+ 1587:3 1583:x 1523:( 1505:( 1483:n 1479:x 1448:( 1407:( 1387:0 1384:= 1381:3 1378:+ 1375:t 1372:+ 1367:5 1363:t 1342:5 1339:= 1336:n 1316:0 1313:= 1310:3 1307:+ 1304:t 1301:+ 1296:3 1292:t 1281:t 1267:1 1261:n 1247:n 1233:5 1227:n 1184:n 1179:1 1175:a 1166:t 1163:= 1160:x 1132:0 1129:= 1126:. 1123:. 1120:. 1115:2 1109:n 1105:x 1099:2 1095:a 1091:+ 1086:1 1080:n 1076:x 1070:1 1066:a 1062:+ 1057:n 1053:x 1008:I 974:3 971:+ 968:t 965:= 962:x 942:x 922:t 882:0 879:= 876:) 873:1 867:t 864:( 861:) 858:1 855:+ 852:t 849:( 846:t 816:0 813:= 810:t 802:3 798:t 767:0 764:= 755:) 752:3 749:+ 746:t 743:( 737:+ 732:2 728:) 724:3 721:+ 718:t 715:( 712:9 704:3 700:) 696:3 693:+ 690:t 687:( 658:3 655:+ 652:t 649:= 646:x 617:2 613:x 587:3 584:a 576:t 573:= 570:x 540:0 537:= 528:x 522:+ 517:2 513:x 509:9 501:3 497:x 466:0 463:= 460:) 457:4 451:x 448:( 445:) 442:3 436:x 433:( 430:) 427:2 421:x 418:( 338:4 256:( 206:( 186:L 135:(

Index

Knowledge:Reference desk
Archives
Mathematics
Mathematics desk
July 10
Jun
July
Aug
July 12
current reference desk
leap days
JackofOz
13:31, 11 July 2007 (UTC)
Meni Rosenfeld
talk
13:43, 11 July 2007 (UTC)
JackofOz
10:43, 12 July 2007 (UTC)
Gregorian calendar
L
13:44, 11 July 2007 (UTC)
Meni Rosenfeld
talk
13:55, 11 July 2007 (UTC)
Gregorian calendar
Julian calendar
Gandalf61
14:17, 11 July 2007 (UTC)
Meni Rosenfeld
talk

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