Arithmetic Progression: x, x + y, x + 2y, x + 3y are said to be in A.P. Here x is first term and common difference is y
a) nth term = x + (n – 1) y
b) Sum of n terms = | n | [2x + (n – 1)y] |
2 |
3) 1 + 2 + 3 ± - - - - + n = | n(n + 1) |
2 |
4) (12 + 22 + 32 - - - - + n2) = | n(n + 1) (2n + 1) |
6 |
5) (13 + 23 + 33 - - - - + n3) = | | n(n + 1) | | 2 |
2 |