| an+1 | ||
an, a następnie z ilorazu | ||
| an |
| n(n+1) | ||
2) an= | ||
| 2 |
to proste:
1) an+1= 2*3n+1= 2*3n *31= 6*3n
wiec:
an+1− an = 6*3n − 2*3n = 4*3n
2) podobnie:
| (n+1)(n+1+1) | (n+1)(n+2) | |||
an+1= | = | |||
| 2 | 2 |
| (n+1)(n+2) | n(n+1) | (n+1)( n+2 −n) | (n+1)*2 | |||||
an+1− an = | − | = | = | =
| ||||
| 2 | 2 | 2 | 2 |
| an+1 | |
= ............ | |
| an |