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Grandi's series

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3032: 3459: 3341: 2071:"... problems that arise naturally (i.e., from nature) do have solutions, so the assumption that things will work out eventually is justified experimentally without the need for existence sorts of proof. Assume everything is okay, and if the arrived-at solution works, you were probably right, or at least right enough. ... so why bother with the details that only show up in homework problems?" 1946:"A posteriori, however, the explanation of this lack of shock on the part of the students may be somewhat different. They accepted calmly the absurdity because, after all, 'mathematics is completely abstract and far from reality', and 'with those mathematical transformations you can prove all kinds of nonsense', as one of the boys later said." 2063:"Since series are generally presented without history and separate from applications, the student must wonder not only "What are these things?" but also "Why are we doing this?" The preoccupation with determining convergence but not the sum makes the whole process seem artificial and pointless to many students—and instructors as well." 1895:
as a result of the geometric series formula. Ideally, by searching for the error in reasoning and by investigating the formula for various common ratios, the students would "notice that there are two kinds of series and an implicit conception of convergence will be born". However, the students showed
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as being the average of 0 and 1. Bagni notes that their reasoning, while similar to Leibniz's, lacks the probabilistic basis that was so important to 18th-century mathematics. He concludes that the responses are consistent with a link between historical development and individual development,
1556: 1269: 1412: 1705:. Otherwise these operations can alter the result of summation. Further, the terms of Grandi's series can be rearranged to have its accumulation points at any interval of two or more consecutive integer numbers, not only 0 or 1. For instance, the series 1102: 507: 1991:
The students had been introduced to the idea of an infinite set, but they had no prior experience with infinite series. They were given ten minutes without books or calculators. The 88 responses were categorized as follows:
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The researcher, Giorgio Bagni, interviewed several of the students to determine their reasoning. Some 16 of them justified an answer of 0 using logic similar to that of Grandi and Riccati. Others justified
2059:
Joel Lehmann describes the process of distinguishing between different sum concepts as building a bridge over a conceptual crevasse: the confusion over divergence that dogged 18th-century mathematics.
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of Grandi's series in which each value in the rearranged series corresponds to a value that is at most four positions away from it in the original series; its accumulation points are 3, 4, and 5.
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Lehmann recommends meeting this objection with the same example that was advanced against Euler's treatment of Grandi's series by Jean-Charles Callet. Euler had viewed the sum as the evaluation at
1423: 512: 877:. Still, to the extent that it is important to be able to bracket series at will, and that it is more important to be able to perform arithmetic with them, one can arrive at two conclusions: 2169: 1645: 1151: 1950:
The students were ultimately not immune to the question of convergence; Sierpińska succeeded in engaging them in the issue by linking it to decimal expansions the following day. As soon as
1833:(in which, after five initial +1 terms, the terms alternate in pairs of +1 and −1 terms – the infinitude of both +1s and −1s allows any finite number of 1s or −1s to be prepended, by 88: 1865:. She focused on humanities students with the expectation that their mathematical experience would be less significant than that of their peers studying mathematics and physics, so the 896:
In fact, both of these statements can be made precise and formally proven, but only using well-defined mathematical concepts that arose in the 19th century. After the late 17th-century
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Lehmann, Joel (1995). "Converging Concepts of Series: Learning from History". In Swetz, Frank; Fauvel, John; Bekken, Otto; Johansson, Bengt; Katz, Victor (eds.).
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Thus, by applying parentheses to Grandi's series in different ways, one can obtain either 0 or 1 as a "value". This is closely akin to the general problem of
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It can be shown that it is not valid to perform many seemingly innocuous operations on a series, such as reordering individual terms, unless the series is
708:{\displaystyle {\begin{aligned}S&=1-1+1-1+\ldots ,{\text{ so}}\\1-S&=1-(1-1+1-1+\ldots )=1-1+1-1+\ldots =S\\1-S&=S\\1&=2S,\end{aligned}}} 2338:. Lehman argues that seeing such a conflicting outcome in intuitive evaluations may motivate the need for rigorous definitions and attention to detail. 2400: 2201: 1876:
Sierpińska initially expected the students to balk at assigning a value to Grandi's series, at which point she could shock them by claiming that
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The above manipulations do not consider what the sum of a series rigorously means and how said algebraic methods can be applied to
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However, though it is divergent, it can be manipulated to yield a number of mathematically interesting results. For example, many
1834: 1711: 1551:{\displaystyle \lim _{N\to \infty }\lim _{\varepsilon \to 0}\sum _{n=0}^{N}(-1+\varepsilon )^{n}=\sum _{n=0}^{\infty }(-1)^{n}} 2577: 3157: 2759: 2720: 2695: 2634: 2608: 1264:{\displaystyle \sum _{n=0}^{\infty }(-1+\varepsilon )^{n}={\frac {1}{1-(-1+\varepsilon )}}={\frac {1}{2-\varepsilon }},} 3321: 3152: 2912: 2859: 2751: 3412: 3301: 2358: 2090: 1600: 904:, the tension between these answers fueled what has been characterized as an "endless" and "violent" dispute between 3370: 3311: 36: 3503: 3407: 3402: 3203: 3193: 2425: 2410: 2347: 1407:{\displaystyle \lim _{\varepsilon \to 0}\lim _{N\to \infty }\sum _{n=0}^{N}(-1+\varepsilon )^{n}={\frac {1}{2}}.} 3508: 3397: 3316: 3218: 2852: 1668: 142: 3344: 1110: 3483: 3462: 3363: 3326: 2818: 484: 502:
and using the same algebraic methods that evaluate convergent geometric series to obtain a third value:
3208: 2823: 2712: 1277: 874: 499: 3493: 3488: 3198: 3188: 3178: 2420: 2415: 2405: 1917: 1097:{\displaystyle \lim _{N\to \infty }\sum _{n=0}^{N}r^{n}=\sum _{n=0}^{\infty }r^{n}={\frac {1}{1-r}}.} 2658: 976: 495:. By taking the average of these two "values", one can justify that the series converges to 1/2. 3293: 3115: 480: 120:
are used in mathematics to assign numerical values even to a divergent series. For example, the
2955: 2902: 2653: 2189:. However, Callet pointed out that one could instead view Grandi's series as the evaluation at 348:
On the other hand, a similar bracketing procedure leads to the apparently contradictory result
2745: 3162: 2907: 1592: 941: 777: 3273: 3110: 2879: 1926:, the students' reaction shouldn't be too surprising given that Leibniz and Grandi thought 1702: 720: 2625:
Mathematics, the science of patterns: the search for order in life, mind, and the universe
844: 8: 3498: 3253: 3120: 2430: 1679: 897: 125: 2772:(November 1987). "Humanities students and epistemological obstacles related to limits". 2435: 121: 3428: 3094: 3079: 3051: 3031: 2970: 2797: 2789: 2671: 2623: 1691: 919: 824: 211: 2769: 1855: 3444: 3283: 3084: 3056: 3010: 3000: 2980: 2965: 2801: 2755: 2716: 2706: 2691: 2630: 2604: 2440: 1975: 754: 3268: 3089: 3015: 3005: 2985: 2887: 2781: 2663: 2588: 2083: 1695: 1565: 117: 110: 1957:
caught the students by surprise, the rest of her material "went past their ears".
3046: 2975: 2809: 1987:(addends, infinitely many, are always +1 and –1). What is your opinion about it?" 901: 24: 3278: 3263: 3258: 2937: 2922: 2388: 1858:
introduced Grandi's series to a group of 17-year-old precalculus students at a
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The theory of functions of a real variable and the theory of Fourier's series
905: 113:, meaning that the sequence of partial sums of the series does not converge. 98: 1979:
pupils (between 16 and 18 years old) were given cards asking the following:
3355: 3248: 2990: 2932: 2813: 2683: 2618: 2313:{\displaystyle 1-x^{2}+x^{3}-x^{5}+x^{6}-\cdots ={\tfrac {1+x}{1+x+x^{2}}}} 1866: 106: 1869:
obstacles they exhibit would be more representative of the obstacles that
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In modern mathematics, the sum of an infinite series is defined to be the
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infinity) is also divergent, but some methods may be used to sum it to
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which clearly does not approach any number (although it does have two
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However, as mentioned, the series obtained by switching the limits,
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As a result, many students develop an attitude similar to Euler's:
1952: 1686:, if it exists. The sequence of partial sums of Grandi's series is 338:{\displaystyle (1-1)+(1-1)+(1-1)+(1-1)+\ldots =0+0+0+0+\ldots =0.} 1966: 492: 469:{\displaystyle 1+(-1+1)+(-1+1)+(-1+1)+\ldots =1+0+0+0+\ldots =1.} 109:, who gave a memorable treatment of the series in 1703. It is a 2516: 2514: 2512: 1983:"In 1703, the mathematician Guido Grandi studied the addition: 1862: 1859: 2368: 1970: 2644:
Kline, Morris (November 1983). "Euler and Infinite Series".
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International Journal for Mathematics Teaching and Learning
1823:{\displaystyle 1+1+1+1+1-1-1+1+1-1-1+1+1-1-1+1+1-\cdots } 2739:. Mathematical Association of America. pp. 161–180. 2555: 2553: 2498: 2578:"Infinite Series from History to Mathematics Education" 2472: 2470: 2457: 2455: 2270: 1604: 780: 757: 3224:
1/2 + 1/3 + 1/5 + 1/7 + 1/11 + ⋯ (inverses of primes)
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1 − 1 + 2 − 6 + 24 − 120 + ⋯ (alternating factorials)
2550: 2538: 2204: 2093: 1714: 1603: 1426: 1309: 1280: 1154: 1113: 988: 944: 922: 847: 827: 723: 510: 357: 223: 145: 39: 2744:Protter, Murray H.; Morrey, Charles B. Jr. (1991). 2526: 2467: 2452: 911: 2622: 2312: 2163: 1822: 1649:, which is only defined on the complex unit disk, 1639: 1550: 1406: 1292: 1263: 1137: 1096: 965: 928: 862: 833: 813: 766: 743: 707: 468: 337: 199: 82: 16:Infinite series summing alternating 1 and -1 terms 1973:around the year 2000, third-year and fourth-year 136:One obvious method to find the sum of the series 3475: 1444: 1428: 1327: 1311: 990: 2808: 2164:{\displaystyle 1-x+x^{2}-x^{3}+\cdots =1/(1+x)} 1640:{\displaystyle \textstyle \sum _{n=0}^{N}z^{n}} 751:. The same conclusion results from calculating 2839:One minus one plus one minus one – Numberphile 3371: 2860: 2743: 2504: 83:{\displaystyle \sum _{n=0}^{\infty }(-1)^{n}} 3385: 3307:Hypergeometric function of a matrix argument 2051:although the cultural context is different. 3163:1 + 1/2 + 1/3 + ... (Riemann zeta function) 1694:at 0 and 1). Therefore, Grandi's series is 3378: 3364: 2867: 2853: 2768: 2520: 483:, and variations of this idea, called the 3219:1 + 1/2 + 1/3 + 1/4 + ⋯ (harmonic series) 2688:Theory and Application of Infinite Series 2657: 2874: 2729: 2601:Fourier Series and Orthogonal Functions 2559: 2544: 214:and perform the subtractions in place: 200:{\displaystyle 1-1+1-1+1-1+1-1+\ldots } 3476: 2704: 2617: 2461: 131: 3359: 2848: 2682: 2643: 2598: 2575: 2532: 2492: 2488: 2476: 1873:still be present in lyceum students. 1138:{\displaystyle \varepsilon \in (0,2)} 977:sum to infinity of a geometric series 1999:(18) the result can be either 0 or 1 1835:Hilbert's paradox of the Grand Hotel 3184:1 − 1 + 1 − 1 + ⋯ (Grandi's series) 2365:1 − 2 + 3 − 4 + 5 − 6 + 7 − 8 + ... 2352: 1849: 13: 2774:Educational Studies in Mathematics 2752:Undergraduate Texts in Mathematics 2391:of two copies of Grandi's series. 1524: 1438: 1337: 1171: 1055: 1000: 900:, but before the advent of modern 898:introduction of calculus in Europe 128:of this series are both 1/2. 56: 14: 3520: 3302:Generalized hypergeometric series 2832: 1960: 1293:{\displaystyle \varepsilon \to 0} 3458: 3457: 3340: 3339: 3312:Lauricella hypergeometric series 3030: 1584:is thus seen to be the value at 912:Relation to the geometric series 3322:Riemann's differential equation 2747:A First Course in Real Analysis 2629:. Scientific American Library. 2576:Bagni, Giorgio T. (June 2005). 821:), subtracting the result from 2482: 2359:Occurrences of Grandi's series 2341: 2158: 2146: 1965:In another study conducted in 1662: 1539: 1529: 1496: 1480: 1451: 1435: 1379: 1363: 1334: 1318: 1284: 1231: 1216: 1192: 1176: 1132: 1120: 997: 960: 945: 802: 790: 616: 586: 498:Treating Grandi's series as a 421: 406: 400: 385: 379: 364: 290: 278: 272: 260: 254: 242: 236: 224: 71: 61: 1: 3317:Modular hypergeometric series 3158:1/4 + 1/16 + 1/64 + 1/256 + ⋯ 2568: 2002:(5) the result does not exist 1673: 2599:Davis, Harry F. (May 1989). 2401:1 − 1 + 2 − 6 + 24 − 120 + ⋯ 2348:Summation of Grandi's series 2054: 1896:no shock at being told that 1844: 210:would be to treat it like a 7: 3327:Theta hypergeometric series 2822:(4th, reprinted ed.). 2819:A Course of Modern Analysis 2394: 10: 3525: 3209:Infinite arithmetic series 3153:1/2 + 1/4 + 1/8 + 1/16 + ⋯ 3148:1/2 − 1/4 + 1/8 − 1/16 + ⋯ 2824:Cambridge University Press 2713:Cambridge University Press 2356: 2345: 2026:(2) the result is infinite 1942:to be a plausible result; 1922:. Sierpińska remarks that 1669:History of Grandi's series 1666: 875:divergent geometric series 500:divergent geometric series 3453: 3437: 3421: 3393: 3335: 3292: 3236: 3171: 3140: 3133: 3103: 3072: 3065: 3039: 3028: 2951: 2895: 2886: 2754:. Springer. p. 249. 2505:Protter & Morrey 1991 1300:of series evaluations is 2446: 487:, are sometimes used in 3040:Properties of sequences 2733:Learn from the Masters! 2196:of a different series, 814:{\textstyle -S=(1-S)-1} 485:Eilenberg–Mazur swindle 481:conditional convergence 3504:Mathematical paradoxes 2903:Arithmetic progression 2705:Hobson, E. W. (1907). 2314: 2165: 1898:1 − 1 + 1 − 1 + ··· = 1878:1 − 1 + 1 − 1 + ··· = 1824: 1641: 1625: 1552: 1528: 1479: 1408: 1362: 1294: 1265: 1175: 1139: 1098: 1059: 1025: 967: 966:{\displaystyle (-1,1)} 930: 864: 835: 815: 768: 745: 709: 470: 339: 201: 84: 60: 3294:Hypergeometric series 2908:Geometric progression 2315: 2166: 1825: 1703:absolutely convergent 1680:limit of the sequence 1642: 1605: 1593:analytic continuation 1553: 1508: 1459: 1409: 1342: 1295: 1266: 1155: 1140: 1099: 1039: 1005: 979:can be evaluated via 968: 931: 865: 836: 816: 769: 746: 744:{\displaystyle S=1/2} 710: 471: 340: 202: 85: 40: 3509:Parity (mathematics) 3274:Trigonometric series 3066:Properties of series 2913:Harmonic progression 2646:Mathematics Magazine 2202: 2091: 1996:(26) the result is 0 1712: 1601: 1424: 1307: 1278: 1152: 1111: 986: 942: 920: 863:{\displaystyle 2S=1} 845: 825: 778: 755: 721: 508: 355: 221: 143: 93:is sometimes called 37: 3254:Formal power series 2431:Ramanujan summation 2023:(3) the result is 1 1985:1 − 1 + 1 − 1 + ... 1692:accumulation points 883:1 − 1 + 1 − 1 + ... 132:Nonrigorous methods 126:Ramanujan summation 3429:Luigi Guido Grandi 3052:Monotonic function 2971:Fibonacci sequence 2786:10.1007/BF00240986 2523:, pp. 371–378 2310: 2308: 2161: 2005:(4) the result is 1820: 1637: 1636: 1548: 1458: 1442: 1404: 1341: 1325: 1290: 1261: 1135: 1094: 1004: 963: 926: 860: 831: 811: 764: 741: 705: 703: 466: 335: 212:telescoping series 197: 80: 3471: 3470: 3353: 3352: 3284:Generating series 3232: 3231: 3204:1 − 2 + 4 − 8 + ⋯ 3199:1 + 2 + 4 + 8 + ⋯ 3194:1 − 2 + 3 − 4 + ⋯ 3189:1 + 2 + 3 + 4 + ⋯ 3179:1 + 1 + 1 + 1 + ⋯ 3129: 3128: 3057:Periodic sequence 3026: 3025: 3011:Triangular number 3001:Pentagonal number 2981:Heptagonal number 2966:Complete sequence 2888:Integer sequences 2841:, Grandi's series 2761:978-0-387-97437-8 2722:978-1-4181-8651-7 2697:978-0-486-66165-0 2636:978-0-7167-6022-1 2610:978-0-486-65973-2 2426:1 − 2 + 4 − 8 + ⋯ 2421:1 + 2 + 4 + 8 + ⋯ 2416:1 + 2 + 3 + 4 + ⋯ 2411:1 − 2 + 3 − 4 + ⋯ 2406:1 + 1 + 1 + 1 + ⋯ 2322:, giving the sum 2307: 2173:, giving the sum 1976:Liceo Scientifico 1918:1 + 2 + 4 + 8 + ⋯ 1443: 1427: 1399: 1326: 1310: 1274:and so the limit 1256: 1235: 1145:, one thus finds 1089: 989: 929:{\displaystyle r} 834:{\displaystyle S} 558: 118:summation methods 28:1 − 1 + 1 − 1 + ⋯ 3516: 3494:Geometric series 3489:Divergent series 3461: 3460: 3380: 3373: 3366: 3357: 3356: 3343: 3342: 3269:Dirichlet series 3138: 3137: 3070: 3069: 3034: 3006:Polygonal number 2986:Hexagonal number 2959: 2893: 2892: 2869: 2862: 2855: 2846: 2845: 2827: 2810:Whittaker, E. T. 2805: 2770:Sierpińska, Anna 2765: 2740: 2738: 2726: 2701: 2679: 2661: 2640: 2628: 2614: 2595: 2593: 2587:. Archived from 2582: 2563: 2557: 2548: 2542: 2536: 2530: 2524: 2518: 2507: 2502: 2496: 2486: 2480: 2474: 2465: 2459: 2436:Cesàro summation 2386: 2384: 2383: 2380: 2377: 2366: 2353:Related problems 2337: 2335: 2334: 2331: 2328: 2321: 2319: 2317: 2316: 2311: 2309: 2306: 2305: 2304: 2282: 2271: 2259: 2258: 2246: 2245: 2233: 2232: 2220: 2219: 2195: 2188: 2186: 2185: 2182: 2179: 2172: 2170: 2168: 2167: 2162: 2145: 2128: 2127: 2115: 2114: 2084:geometric series 2081: 2049: 2047: 2046: 2043: 2040: 2020: 2018: 2017: 2014: 2011: 1986: 1956: 1941: 1939: 1938: 1935: 1932: 1921: 1914: 1913: 1911: 1910: 1907: 1904: 1894: 1893: 1891: 1890: 1887: 1884: 1850:Cognitive impact 1829: 1827: 1826: 1821: 1689: 1688:1, 0, 1, 0, ..., 1658: 1656: 1648: 1646: 1644: 1643: 1638: 1635: 1634: 1624: 1619: 1590: 1583: 1581: 1580: 1577: 1574: 1566:complex analysis 1564:In the terms of 1557: 1555: 1554: 1549: 1547: 1546: 1527: 1522: 1504: 1503: 1478: 1473: 1457: 1441: 1413: 1411: 1410: 1405: 1400: 1392: 1387: 1386: 1361: 1356: 1340: 1324: 1299: 1297: 1296: 1291: 1270: 1268: 1267: 1262: 1257: 1255: 1241: 1236: 1234: 1205: 1200: 1199: 1174: 1169: 1144: 1142: 1141: 1136: 1103: 1101: 1100: 1095: 1090: 1088: 1074: 1069: 1068: 1058: 1053: 1035: 1034: 1024: 1019: 1003: 974: 972: 970: 969: 964: 936:in the interval 935: 933: 932: 927: 888:... but its sum 884: 869: 867: 866: 861: 840: 838: 837: 832: 820: 818: 817: 812: 773: 771: 770: 765: 750: 748: 747: 742: 737: 714: 712: 711: 706: 704: 559: 556: 475: 473: 472: 467: 344: 342: 341: 336: 206: 204: 203: 198: 122:Cesàro summation 111:divergent series 97:, after Italian 89: 87: 86: 81: 79: 78: 59: 54: 29: 3524: 3523: 3519: 3518: 3517: 3515: 3514: 3513: 3484:Grandi's series 3474: 3473: 3472: 3467: 3449: 3433: 3417: 3389: 3387:Grandi's series 3384: 3354: 3349: 3331: 3288: 3237:Kinds of series 3228: 3167: 3134:Explicit series 3125: 3099: 3061: 3047:Cauchy sequence 3035: 3022: 2976:Figurate number 2953: 2947: 2938:Powers of three 2882: 2873: 2835: 2830: 2762: 2736: 2723: 2715:. section 331. 2698: 2668:10.2307/2690371 2659:10.1.1.639.6923 2637: 2611: 2591: 2580: 2571: 2566: 2558: 2551: 2543: 2539: 2531: 2527: 2521:Sierpińska 1987 2519: 2510: 2503: 2499: 2491:, p. 307; 2487: 2483: 2475: 2468: 2460: 2453: 2449: 2397: 2381: 2378: 2375: 2374: 2372: 2364: 2361: 2355: 2350: 2344: 2332: 2329: 2326: 2325: 2323: 2300: 2296: 2283: 2272: 2269: 2254: 2250: 2241: 2237: 2228: 2224: 2215: 2211: 2203: 2200: 2199: 2197: 2190: 2183: 2180: 2177: 2176: 2174: 2141: 2123: 2119: 2110: 2106: 2092: 2089: 2088: 2086: 2076: 2057: 2044: 2041: 2038: 2037: 2035: 2015: 2012: 2009: 2008: 2006: 1984: 1963: 1951: 1936: 1933: 1930: 1929: 1927: 1916: 1908: 1905: 1902: 1901: 1899: 1897: 1888: 1885: 1882: 1881: 1879: 1877: 1867:epistemological 1856:Anna Sierpińska 1852: 1847: 1713: 1710: 1709: 1687: 1676: 1671: 1665: 1652: 1650: 1630: 1626: 1620: 1609: 1602: 1599: 1598: 1596: 1585: 1578: 1575: 1572: 1571: 1569: 1542: 1538: 1523: 1512: 1499: 1495: 1474: 1463: 1447: 1431: 1425: 1422: 1421: 1391: 1382: 1378: 1357: 1346: 1330: 1314: 1308: 1305: 1304: 1279: 1276: 1275: 1245: 1240: 1209: 1204: 1195: 1191: 1170: 1159: 1153: 1150: 1149: 1112: 1109: 1108: 1078: 1073: 1064: 1060: 1054: 1043: 1030: 1026: 1020: 1009: 993: 987: 984: 983: 943: 940: 939: 937: 921: 918: 917: 916:For any number 914: 882: 846: 843: 842: 826: 823: 822: 779: 776: 775: 767:{\textstyle -S} 756: 753: 752: 733: 722: 719: 718: 702: 701: 685: 679: 678: 668: 656: 655: 573: 561: 560: 555: 518: 511: 509: 506: 505: 356: 353: 352: 222: 219: 218: 144: 141: 140: 134: 95:Grandi's series 74: 70: 55: 44: 38: 35: 34: 30:, also written 27: 25:infinite series 17: 12: 11: 5: 3522: 3512: 3511: 3506: 3501: 3496: 3491: 3486: 3469: 3468: 3466: 3465: 3454: 3451: 3450: 3448: 3447: 3445:Thomson's lamp 3441: 3439: 3435: 3434: 3432: 3431: 3425: 3423: 3419: 3418: 3416: 3415: 3410: 3405: 3400: 3394: 3391: 3390: 3383: 3382: 3375: 3368: 3360: 3351: 3350: 3348: 3347: 3336: 3333: 3332: 3330: 3329: 3324: 3319: 3314: 3309: 3304: 3298: 3296: 3290: 3289: 3287: 3286: 3281: 3279:Fourier series 3276: 3271: 3266: 3264:Puiseux series 3261: 3259:Laurent series 3256: 3251: 3246: 3240: 3238: 3234: 3233: 3230: 3229: 3227: 3226: 3221: 3216: 3211: 3206: 3201: 3196: 3191: 3186: 3181: 3175: 3173: 3169: 3168: 3166: 3165: 3160: 3155: 3150: 3144: 3142: 3135: 3131: 3130: 3127: 3126: 3124: 3123: 3118: 3113: 3107: 3105: 3101: 3100: 3098: 3097: 3092: 3087: 3082: 3076: 3074: 3067: 3063: 3062: 3060: 3059: 3054: 3049: 3043: 3041: 3037: 3036: 3029: 3027: 3024: 3023: 3021: 3020: 3019: 3018: 3008: 3003: 2998: 2993: 2988: 2983: 2978: 2973: 2968: 2962: 2960: 2949: 2948: 2946: 2945: 2940: 2935: 2930: 2925: 2920: 2915: 2910: 2905: 2899: 2897: 2890: 2884: 2883: 2872: 2871: 2864: 2857: 2849: 2843: 2842: 2834: 2833:External links 2831: 2829: 2828: 2806: 2780:(4): 371–396. 2766: 2760: 2741: 2727: 2721: 2702: 2696: 2680: 2652:(5): 307–314. 2641: 2635: 2615: 2609: 2596: 2594:on 2006-12-29. 2572: 2570: 2567: 2565: 2564: 2549: 2537: 2535:, pp. 6–8 2525: 2508: 2497: 2481: 2466: 2450: 2448: 2445: 2444: 2443: 2441:Thomson's lamp 2438: 2433: 2428: 2423: 2418: 2413: 2408: 2403: 2396: 2393: 2389:Cauchy product 2357:Main article: 2354: 2351: 2346:Main article: 2343: 2340: 2303: 2299: 2295: 2292: 2289: 2286: 2281: 2278: 2275: 2268: 2265: 2262: 2257: 2253: 2249: 2244: 2240: 2236: 2231: 2227: 2223: 2218: 2214: 2210: 2207: 2160: 2157: 2154: 2151: 2148: 2144: 2140: 2137: 2134: 2131: 2126: 2122: 2118: 2113: 2109: 2105: 2102: 2099: 2096: 2073: 2072: 2065: 2064: 2056: 2053: 2031: 2030: 2029:(30) no answer 2027: 2024: 2021: 2003: 2000: 1997: 1989: 1988: 1962: 1961:Preconceptions 1959: 1948: 1947: 1851: 1848: 1846: 1843: 1831: 1830: 1819: 1816: 1813: 1810: 1807: 1804: 1801: 1798: 1795: 1792: 1789: 1786: 1783: 1780: 1777: 1774: 1771: 1768: 1765: 1762: 1759: 1756: 1753: 1750: 1747: 1744: 1741: 1738: 1735: 1732: 1729: 1726: 1723: 1720: 1717: 1675: 1672: 1667:Main article: 1664: 1661: 1633: 1629: 1623: 1618: 1615: 1612: 1608: 1595:of the series 1561:is divergent. 1559: 1558: 1545: 1541: 1537: 1534: 1531: 1526: 1521: 1518: 1515: 1511: 1507: 1502: 1498: 1494: 1491: 1488: 1485: 1482: 1477: 1472: 1469: 1466: 1462: 1456: 1453: 1450: 1446: 1440: 1437: 1434: 1430: 1415: 1414: 1403: 1398: 1395: 1390: 1385: 1381: 1377: 1374: 1371: 1368: 1365: 1360: 1355: 1352: 1349: 1345: 1339: 1336: 1333: 1329: 1323: 1320: 1317: 1313: 1289: 1286: 1283: 1272: 1271: 1260: 1254: 1251: 1248: 1244: 1239: 1233: 1230: 1227: 1224: 1221: 1218: 1215: 1212: 1208: 1203: 1198: 1194: 1190: 1187: 1184: 1181: 1178: 1173: 1168: 1165: 1162: 1158: 1134: 1131: 1128: 1125: 1122: 1119: 1116: 1105: 1104: 1093: 1087: 1084: 1081: 1077: 1072: 1067: 1063: 1057: 1052: 1049: 1046: 1042: 1038: 1033: 1029: 1023: 1018: 1015: 1012: 1008: 1002: 999: 996: 992: 962: 959: 956: 953: 950: 947: 925: 913: 910: 906:mathematicians 894: 893: 886: 859: 856: 853: 850: 841:, and solving 830: 810: 807: 804: 801: 798: 795: 792: 789: 786: 783: 763: 760: 740: 736: 732: 729: 726: 700: 697: 694: 691: 688: 686: 684: 681: 680: 677: 674: 671: 669: 667: 664: 661: 658: 657: 654: 651: 648: 645: 642: 639: 636: 633: 630: 627: 624: 621: 618: 615: 612: 609: 606: 603: 600: 597: 594: 591: 588: 585: 582: 579: 576: 574: 572: 569: 566: 563: 562: 554: 551: 548: 545: 542: 539: 536: 533: 530: 527: 524: 521: 519: 517: 514: 513: 477: 476: 465: 462: 459: 456: 453: 450: 447: 444: 441: 438: 435: 432: 429: 426: 423: 420: 417: 414: 411: 408: 405: 402: 399: 396: 393: 390: 387: 384: 381: 378: 375: 372: 369: 366: 363: 360: 346: 345: 334: 331: 328: 325: 322: 319: 316: 313: 310: 307: 304: 301: 298: 295: 292: 289: 286: 283: 280: 277: 274: 271: 268: 265: 262: 259: 256: 253: 250: 247: 244: 241: 238: 235: 232: 229: 226: 208: 207: 196: 193: 190: 187: 184: 181: 178: 175: 172: 169: 166: 163: 160: 157: 154: 151: 148: 133: 130: 91: 90: 77: 73: 69: 66: 63: 58: 53: 50: 47: 43: 15: 9: 6: 4: 3: 2: 3521: 3510: 3507: 3505: 3502: 3500: 3497: 3495: 3492: 3490: 3487: 3485: 3482: 3481: 3479: 3464: 3456: 3455: 3452: 3446: 3443: 3442: 3440: 3436: 3430: 3427: 3426: 3424: 3420: 3414: 3411: 3409: 3406: 3404: 3401: 3399: 3396: 3395: 3392: 3388: 3381: 3376: 3374: 3369: 3367: 3362: 3361: 3358: 3346: 3338: 3337: 3334: 3328: 3325: 3323: 3320: 3318: 3315: 3313: 3310: 3308: 3305: 3303: 3300: 3299: 3297: 3295: 3291: 3285: 3282: 3280: 3277: 3275: 3272: 3270: 3267: 3265: 3262: 3260: 3257: 3255: 3252: 3250: 3247: 3245: 3244:Taylor series 3242: 3241: 3239: 3235: 3225: 3222: 3220: 3217: 3215: 3212: 3210: 3207: 3205: 3202: 3200: 3197: 3195: 3192: 3190: 3187: 3185: 3182: 3180: 3177: 3176: 3174: 3170: 3164: 3161: 3159: 3156: 3154: 3151: 3149: 3146: 3145: 3143: 3139: 3136: 3132: 3122: 3119: 3117: 3114: 3112: 3109: 3108: 3106: 3102: 3096: 3093: 3091: 3088: 3086: 3083: 3081: 3078: 3077: 3075: 3071: 3068: 3064: 3058: 3055: 3053: 3050: 3048: 3045: 3044: 3042: 3038: 3033: 3017: 3014: 3013: 3012: 3009: 3007: 3004: 3002: 2999: 2997: 2994: 2992: 2989: 2987: 2984: 2982: 2979: 2977: 2974: 2972: 2969: 2967: 2964: 2963: 2961: 2957: 2950: 2944: 2941: 2939: 2936: 2934: 2933:Powers of two 2931: 2929: 2926: 2924: 2921: 2919: 2918:Square number 2916: 2914: 2911: 2909: 2906: 2904: 2901: 2900: 2898: 2894: 2891: 2889: 2885: 2881: 2877: 2870: 2865: 2863: 2858: 2856: 2851: 2850: 2847: 2840: 2837: 2836: 2825: 2821: 2820: 2815: 2814:Watson, G. N. 2811: 2807: 2803: 2799: 2795: 2791: 2787: 2783: 2779: 2775: 2771: 2767: 2763: 2757: 2753: 2749: 2748: 2742: 2735: 2734: 2728: 2724: 2718: 2714: 2710: 2709: 2703: 2699: 2693: 2689: 2685: 2684:Knopp, Konrad 2681: 2677: 2673: 2669: 2665: 2660: 2655: 2651: 2647: 2642: 2638: 2632: 2627: 2626: 2620: 2619:Devlin, Keith 2616: 2612: 2606: 2602: 2597: 2590: 2586: 2579: 2574: 2573: 2562:, p. 176 2561: 2556: 2554: 2547:, p. 165 2546: 2541: 2534: 2529: 2522: 2517: 2515: 2513: 2506: 2501: 2495:, p. 457 2494: 2490: 2485: 2479:, p. 152 2478: 2473: 2471: 2463: 2458: 2456: 2451: 2442: 2439: 2437: 2434: 2432: 2429: 2427: 2424: 2422: 2419: 2417: 2414: 2412: 2409: 2407: 2404: 2402: 2399: 2398: 2392: 2390: 2370: 2360: 2349: 2339: 2301: 2297: 2293: 2290: 2287: 2284: 2279: 2276: 2273: 2266: 2263: 2260: 2255: 2251: 2247: 2242: 2238: 2234: 2229: 2225: 2221: 2216: 2212: 2208: 2205: 2193: 2155: 2152: 2149: 2142: 2138: 2135: 2132: 2129: 2124: 2120: 2116: 2111: 2107: 2103: 2100: 2097: 2094: 2085: 2079: 2070: 2069: 2068: 2062: 2061: 2060: 2052: 2028: 2025: 2022: 2004: 2001: 1998: 1995: 1994: 1993: 1982: 1981: 1980: 1978: 1977: 1972: 1968: 1958: 1954: 1945: 1944: 1943: 1925: 1919: 1915:or even that 1874: 1872: 1868: 1864: 1861: 1857: 1854:Around 1987, 1842: 1840: 1836: 1817: 1814: 1811: 1808: 1805: 1802: 1799: 1796: 1793: 1790: 1787: 1784: 1781: 1778: 1775: 1772: 1769: 1766: 1763: 1760: 1757: 1754: 1751: 1748: 1745: 1742: 1739: 1736: 1733: 1730: 1727: 1724: 1721: 1718: 1715: 1708: 1707: 1706: 1704: 1699: 1697: 1693: 1685: 1681: 1670: 1660: 1657:| < 1 1655: 1631: 1627: 1621: 1616: 1613: 1610: 1606: 1594: 1588: 1567: 1562: 1543: 1535: 1532: 1519: 1516: 1513: 1509: 1505: 1500: 1492: 1489: 1486: 1483: 1475: 1470: 1467: 1464: 1460: 1454: 1448: 1432: 1420: 1419: 1418: 1401: 1396: 1393: 1388: 1383: 1375: 1372: 1369: 1366: 1358: 1353: 1350: 1347: 1343: 1331: 1321: 1315: 1303: 1302: 1301: 1287: 1281: 1258: 1252: 1249: 1246: 1242: 1237: 1228: 1225: 1222: 1219: 1213: 1210: 1206: 1201: 1196: 1188: 1185: 1182: 1179: 1166: 1163: 1160: 1156: 1148: 1147: 1146: 1129: 1126: 1123: 1117: 1114: 1091: 1085: 1082: 1079: 1075: 1070: 1065: 1061: 1050: 1047: 1044: 1040: 1036: 1031: 1027: 1021: 1016: 1013: 1010: 1006: 994: 982: 981: 980: 978: 957: 954: 951: 948: 923: 909: 907: 903: 899: 891: 887: 880: 879: 878: 876: 871: 857: 854: 851: 848: 828: 808: 805: 799: 796: 793: 787: 784: 781: 761: 758: 738: 734: 730: 727: 724: 717:resulting in 715: 698: 695: 692: 689: 687: 682: 675: 672: 670: 665: 662: 659: 652: 649: 646: 643: 640: 637: 634: 631: 628: 625: 622: 619: 613: 610: 607: 604: 601: 598: 595: 592: 589: 583: 580: 577: 575: 570: 567: 564: 552: 549: 546: 543: 540: 537: 534: 531: 528: 525: 522: 520: 515: 503: 501: 496: 494: 490: 486: 482: 463: 460: 457: 454: 451: 448: 445: 442: 439: 436: 433: 430: 427: 424: 418: 415: 412: 409: 403: 397: 394: 391: 388: 382: 376: 373: 370: 367: 361: 358: 351: 350: 349: 332: 329: 326: 323: 320: 317: 314: 311: 308: 305: 302: 299: 296: 293: 287: 284: 281: 275: 269: 266: 263: 257: 251: 248: 245: 239: 233: 230: 227: 217: 216: 215: 213: 194: 191: 188: 185: 182: 179: 176: 173: 170: 167: 164: 161: 158: 155: 152: 149: 146: 139: 138: 137: 129: 127: 123: 119: 114: 112: 108: 105:, and priest 104: 100: 99:mathematician 96: 75: 67: 64: 51: 48: 45: 41: 33: 32: 31: 26: 22: 3386: 3249:Power series 3183: 2991:Lucas number 2943:Powers of 10 2923:Cubic number 2817: 2777: 2773: 2746: 2732: 2707: 2687: 2649: 2645: 2624: 2600: 2589:the original 2584: 2560:Lehmann 1995 2545:Lehmann 1995 2540: 2528: 2500: 2484: 2464:, p. 77 2362: 2191: 2077: 2074: 2066: 2058: 2032: 1990: 1974: 1964: 1949: 1923: 1875: 1870: 1853: 1832: 1700: 1684:partial sums 1677: 1653: 1586: 1563: 1560: 1416: 1273: 1106: 915: 895: 889: 872: 716: 504: 497: 478: 347: 209: 135: 115: 107:Guido Grandi 94: 92: 18: 3413:Occurrences 3116:Conditional 3104:Convergence 3095:Telescoping 3080:Alternating 2996:Pell number 2462:Devlin 1994 2363:The series 2342:Summability 1839:permutation 1663:Early ideas 885:has no sum. 881:The series 489:knot theory 103:philosopher 21:mathematics 3499:1 (number) 3478:Categories 3141:Convergent 3085:Convergent 2569:References 2533:Bagni 2005 2493:Knopp 1990 2489:Kline 1983 2477:Davis 1989 1674:Divergence 3408:Summation 3403:Education 3172:Divergent 3090:Divergent 2952:Advanced 2928:Factorial 2876:Sequences 2802:144880659 2690:. Dover. 2686:(1990) . 2654:CiteSeerX 2603:. Dover. 2264:⋯ 2261:− 2235:− 2209:− 2133:⋯ 2117:− 2098:− 2055:Prospects 1845:Education 1818:⋯ 1815:− 1797:− 1791:− 1773:− 1767:− 1749:− 1743:− 1696:divergent 1607:∑ 1533:− 1525:∞ 1510:∑ 1493:ε 1484:− 1461:∑ 1452:→ 1449:ε 1439:∞ 1436:→ 1376:ε 1367:− 1344:∑ 1338:∞ 1335:→ 1319:→ 1316:ε 1285:→ 1282:ε 1253:ε 1250:− 1229:ε 1220:− 1214:− 1189:ε 1180:− 1172:∞ 1157:∑ 1118:∈ 1115:ε 1083:− 1056:∞ 1041:∑ 1007:∑ 1001:∞ 998:→ 949:− 806:− 797:− 782:− 759:− 663:− 647:… 638:− 626:− 614:… 605:− 593:− 584:− 568:− 550:… 541:− 529:− 458:… 428:… 410:− 389:− 368:− 327:… 297:… 285:− 267:− 249:− 231:− 195:… 186:− 174:− 162:− 150:− 65:− 57:∞ 42:∑ 3463:Category 3345:Category 3111:Absolute 2826:. § 2.1. 2816:(1962). 2621:(1994). 2395:See also 1953:0.999... 1924:a priori 1107:For any 557: so 124:and the 3438:Related 3398:History 3121:Uniform 2794:3482354 2676:2690371 2385:⁠ 2373:⁠ 2336:⁠ 2324:⁠ 2320:⁠ 2198:⁠ 2187:⁠ 2175:⁠ 2171:⁠ 2087:⁠ 2082:of the 2048:⁠ 2036:⁠ 2019:⁠ 2007:⁠ 1967:Treviso 1940:⁠ 1928:⁠ 1912:⁠ 1900:⁠ 1892:⁠ 1880:⁠ 1837:) is a 1682:of its 1647:⁠ 1597:⁠ 1591:of the 1582:⁠ 1570:⁠ 973:⁠ 938:⁠ 892:be 1/2. 774:(from ( 493:algebra 3422:People 3073:Series 2880:series 2800:  2792:  2758:  2719:  2694:  2674:  2656:  2633:  2607:  1863:lyceum 1860:Warsaw 1651:| 975:, the 902:rigour 890:should 23:, the 3016:array 2896:Basic 2798:S2CID 2790:JSTOR 2737:(PDF) 2672:JSTOR 2592:(PDF) 2581:(PDF) 2447:Notes 2369:up to 1971:Italy 2956:list 2878:and 2756:ISBN 2717:ISBN 2692:ISBN 2631:ISBN 2605:ISBN 1920:= −1 1589:= −1 491:and 2782:doi 2664:doi 2194:= 1 2080:= 1 1955:= 1 1871:may 1445:lim 1429:lim 1328:lim 1312:lim 991:lim 19:In 3480:: 2812:; 2796:. 2788:. 2778:18 2776:. 2750:. 2711:. 2670:. 2662:. 2650:56 2648:. 2583:. 2552:^ 2511:^ 2469:^ 2454:^ 1969:, 1698:. 1659:. 1568:, 908:. 870:. 464:1. 333:0. 101:, 3379:e 3372:t 3365:v 2958:) 2954:( 2868:e 2861:t 2854:v 2804:. 2784:: 2764:. 2725:. 2700:. 2678:. 2666:: 2639:. 2613:. 2382:4 2379:/ 2376:1 2367:( 2333:3 2330:/ 2327:2 2302:2 2298:x 2294:+ 2291:x 2288:+ 2285:1 2280:x 2277:+ 2274:1 2267:= 2256:6 2252:x 2248:+ 2243:5 2239:x 2230:3 2226:x 2222:+ 2217:2 2213:x 2206:1 2192:x 2184:2 2181:/ 2178:1 2159:) 2156:x 2153:+ 2150:1 2147:( 2143:/ 2139:1 2136:= 2130:+ 2125:3 2121:x 2112:2 2108:x 2104:+ 2101:x 2095:1 2078:x 2045:2 2042:/ 2039:1 2016:2 2013:/ 2010:1 1937:2 1934:/ 1931:1 1909:2 1906:/ 1903:1 1889:2 1886:/ 1883:1 1812:1 1809:+ 1806:1 1803:+ 1800:1 1794:1 1788:1 1785:+ 1782:1 1779:+ 1776:1 1770:1 1764:1 1761:+ 1758:1 1755:+ 1752:1 1746:1 1740:1 1737:+ 1734:1 1731:+ 1728:1 1725:+ 1722:1 1719:+ 1716:1 1654:z 1632:n 1628:z 1622:N 1617:0 1614:= 1611:n 1587:z 1579:2 1576:/ 1573:1 1544:n 1540:) 1536:1 1530:( 1520:0 1517:= 1514:n 1506:= 1501:n 1497:) 1490:+ 1487:1 1481:( 1476:N 1471:0 1468:= 1465:n 1455:0 1433:N 1402:. 1397:2 1394:1 1389:= 1384:n 1380:) 1373:+ 1370:1 1364:( 1359:N 1354:0 1351:= 1348:n 1332:N 1322:0 1288:0 1259:, 1247:2 1243:1 1238:= 1232:) 1226:+ 1223:1 1217:( 1211:1 1207:1 1202:= 1197:n 1193:) 1186:+ 1183:1 1177:( 1167:0 1164:= 1161:n 1133:) 1130:2 1127:, 1124:0 1121:( 1092:. 1086:r 1080:1 1076:1 1071:= 1066:n 1062:r 1051:0 1048:= 1045:n 1037:= 1032:n 1028:r 1022:N 1017:0 1014:= 1011:n 995:N 961:) 958:1 955:, 952:1 946:( 924:r 858:1 855:= 852:S 849:2 829:S 809:1 803:) 800:S 794:1 791:( 788:= 785:S 762:S 739:2 735:/ 731:1 728:= 725:S 699:, 696:S 693:2 690:= 683:1 676:S 673:= 666:S 660:1 653:S 650:= 644:+ 641:1 635:1 632:+ 629:1 623:1 620:= 617:) 611:+ 608:1 602:1 599:+ 596:1 590:1 587:( 581:1 578:= 571:S 565:1 553:, 547:+ 544:1 538:1 535:+ 532:1 526:1 523:= 516:S 461:= 455:+ 452:0 449:+ 446:0 443:+ 440:0 437:+ 434:1 431:= 425:+ 422:) 419:1 416:+ 413:1 407:( 404:+ 401:) 398:1 395:+ 392:1 386:( 383:+ 380:) 377:1 374:+ 371:1 365:( 362:+ 359:1 330:= 324:+ 321:0 318:+ 315:0 312:+ 309:0 306:+ 303:0 300:= 294:+ 291:) 288:1 282:1 279:( 276:+ 273:) 270:1 264:1 261:( 258:+ 255:) 252:1 246:1 243:( 240:+ 237:) 234:1 228:1 225:( 192:+ 189:1 183:1 180:+ 177:1 171:1 168:+ 165:1 159:1 156:+ 153:1 147:1 76:n 72:) 68:1 62:( 52:0 49:= 46:n

Index

mathematics
infinite series
mathematician
philosopher
Guido Grandi
divergent series
summation methods
Cesàro summation
Ramanujan summation
telescoping series
conditional convergence
Eilenberg–Mazur swindle
knot theory
algebra
divergent geometric series
divergent geometric series
introduction of calculus in Europe
rigour
mathematicians
sum to infinity of a geometric series
complex analysis
analytic continuation
History of Grandi's series
limit of the sequence
partial sums
accumulation points
divergent
absolutely convergent
Hilbert's paradox of the Grand Hotel
permutation

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