| 1 | ||
a) 1+2+3+...+n = ∑ k= | n(n+1) | |
| 2 |
| 1 | ||
b) ∑ k2 = | n(n+1)(2n+1) | |
| 6 |
| 1 | ||
12+22+....+n2 = | n(n+1)(2n+1) | |
| 6 |
| 1 | ||
P = | *1*2*3 = 1 | |
| 6 |
| 1 | ||
12+22+....+n2 = | n(n+1)(2n+1) | |
| 6 |
| 1 | 1 | |||
12+22+....+n2+(n+1)2 = | (n+1)(n+2)(2(n+1)+1) = | (n+1)(n+2)(2n+3) | ||
| 6 | 6 |
| 1 | ||
12+22+....+n2+(n+1)2 = | n(n+1)(2n+1) + (n+1)2 = | |
| 6 |
| 1 | ||
(n+1)*[ | n(2n+1)+(n+1) ] = | |
| 6 |
| n(2n+1)+6(n+1) | ||
(n+1)* | = | |
| 6 |
| 2n2+n+6n+6 | ||
(n+1)* | = | |
| 6 |
| 2n2+7n+6 | ||
(n+1)* | = | |
| 6 |
| −7−1 | −7+1 | 6 | 3 | |||||
[ Δ = 49−48=1 n1 = | = −2 n2 = | = − | = − | ] | ||||
| 4 | 4 | 4 | 2 |
| (n+2)(2n+3) | 1 | |||
(n+1)* | = | (n+1)(n+2)(2n+3) | ||
| 6 | 6 |