| 1 | 1 | 1 | 1 | |||||
un = (1 − | ) * (1 − | ) * (1 − | ) * ... * (1 − | ) | ||||
| 22 | 32 | 42 | n2 |
| k2 − 1 | k − 1 | k + 1 | |||
= | * | ||||
| k2 | k | k |
| 2 − 1 | 2+1 | 3−1 | 3+1 | n−1 | n+1 | ||||||
* | * | * | * .... | * | = .... | ||||||
| 2 | 2 | 3 | 3 | n | n |
| (2−1)(2+1)*...*(n−1)(n+1) | ∏k=2n(k−1)(k+1) | ||
= | = | ||
| 2*2*...*n*n | ∏k=2nk2 |
| ∏k=2n(k−1)∏k=2n(k+1) | ||
= | = | |
| ∏k=2nk2 |
| ∏k=1n−1k∏k=3n+1k | ||
= | = | |
| ∏k=2nk2 |
| (1/n)∏k=2nk((n+1)/2)∏k=2nk | ||
= | = | |
| ∏k=2nk2 |
| n+1 | ||
= | ||
| 2n |
| n+1 | ||
ostatecznie | . Ciekawy sposób Adamm, nie znałem czegoś takiego wcześniej. | |
| 2n |