1, 1, 1 - + - +... + - - - = 2X4, x6, 68, 2008, X2010 1 / 2X4 + 1 / 4X6 + 1 / 6X8 +... + 1 / 2008 X2010

1, 1, 1 - + - +... + - - - = 2X4, x6, 68, 2008, X2010 1 / 2X4 + 1 / 4X6 + 1 / 6X8 +... + 1 / 2008 X2010

1 / 2 * 4 = (1 / 2 - 1 / 4) / 2
1 / 4 * 6 = (1 / 4 - 1 / 6) / 2
...
1 / 2008 * 2010 = (1 / 2008 - 1 / 2010) / 2
원판 = (1 / 2 - 1 / 2010) / 2 = 251 / 1005