| 1 | 1 | 1 | 1 | 1 | |||||
+ | + | +...+ | < 2 − | ||||||
| 12 | 22 | 32 | n2 | n2 |
| 1 | 1 | 1 | 1 | 1 | |||||
+ | + | +...+ | < 2 − | , k≥2, k∊N | |||||
| 12 | 22 | 32 | k2 | k2 |
| 1 | 1 | 1 | 1 | 1 | 1 | ||||||
+ | + | +...+ | + | <2− | |||||||
| 12 | 22 | 32 | k2 | (k+1)2 | k+1 |
| 1 | 1 | ||
+ | +.. | ||
| 12 | 22 |
| 1 | 1 | 1 | 1 | |||||
...+ | + | <2− | + | |||||
| k2 | (k+1)2 | k+1 | (k+1)2 |
| k−(k+1)2 | ||
=2+ | ||
| k(k+1) |
| k−(k+1)2 | 1 | |||
2+ | < 2− | czyli mam | ||
| k(k+1) | k+1 |
| k−(k+1)2 | 1 | ||
+ | < 0 | ||
| k(k+1) | k+1 |
| k−k2−2k−1 | 1 | ||
+ | < 0 | ||
| k(k+1) | k+1 |
| −k2−k−1 | 1 | ||
+ | < 0 | ||
| k(k+1) | k+1 |
| (−k2−k−1)(k+1)+ k(k+1) | |
< 0 | |
| k(k+1)2 |
| −k3−k2−k−1 | |
< 0 | |
| k(k+1)2 |
| (k+1)(−k2−1) | |
< 0 | |
| k(k+1)2 |
| (−k2−1) | |
< 0 | |
| k(k+1) |
| (k2+1) | ||
− | < 0 / *(−1) | |
| k(k+1) |
| (k2+1) | |
> 0 | |
| k(k+1) |