Friday, July 8, 2016
James Grime: 23 and Football Birthdays: Birthday Problem (誕生日のパラドックス)
Command:
$ bc <<< 'scale=10;364/365 * 363/365 * 362/365 * 361/365 * 360/365 * 359/365 * 358/365 * 357/365 * 356/365 * 355/365 * 354/365 * 353/365 * 352/365 * 351/365 * 350/365 * 349/365 * 348/365 * 347/365 * 346/365 * 345/365 * 344/365 * 343/365'
Result:
.4927027648
ラベル:
Birthday problem,
誕生日のパラドックス
Ria Symonds: 7 and Happy Numbers (ハッピー数)
Example: 7
7
7^2 = 49
4^2 + 9^2 = 16 + 81 = 97
9^2 + 7^2 = 81 + 49 = 130
1^2 + 3^2 + 0^2 = 1 + 9 + 0 = 10
1^2 + 0^2 = 1 + 0 = 1
7 is a happy number
Example: 8
8
8^2 = 64
6^2 + 4^2 = 36 + 16 = 52
5^2 + 2^2 = 25 + 4 = 29
2^2 + 9^2 = 4 + 81 = 85
8^2 + 5^2 = 64 + 25 = 89
8^2 + 9^2 = 64 + 81 = 145
1^2 + 4^2 + 5^2 = 1 + 16 + 25 = 42
4^2 + 2^2 = 16 + 4 = 20
2^2 + 0^2 = 4 + 0 = 4
4^2 = 16
1^2 + 6^2 = 1 + 36 = 37
3^2 + 7^2 = 9 + 49 = 58
5^2 + 8^2 = 25 + 64 = 89
8 is not a happy number
ラベル:
Happy number,
ハッピー数
Wednesday, July 6, 2016
James Grime: 14 Super Bowl Coin Tosses
Number of games you have to wait before you have 3 wins in a row:
t = 1/2(1+t) + 1/4(2+t) + 1/8(3+t) + 1/8(3)
t = 14
Number of games you have to wait before you have 14 wins in a row:
t = 1/2(1+t) + 1/4(2+t) + 1/8(3+t) + 1/16(4+t) + ... + 1/16384(14+t) + 1/16384(14)
t = 2 ^ (n+1) - 2
t = 32766
ラベル:
Coin flipping,
Super Bowl,
コイントス,
スーパーボウル
Tuesday, July 5, 2016
Monday, July 4, 2016
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