Sequence and Series help!!!!?

1 ⤊

1. Some numbers given are in sequences..
1, 3, 6, 10..... Derive the formula to find 'n'th term..

2007-03-29 19:17:44 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

Write the terms thus:
1
1+2
1+2+3
1+2+3+4

Seeing a pattern yet? The nth term is [k=1, n]∑k, which is n(n+1)/2

2007-03-29 19:27:04 · answer #1 · answered by Pascal 7 · 1⤊ 0⤋

(n/2)(n+1)

2007-03-30 02:23:06 · answer #2 · answered by Karthik 1 · 0⤊ 1⤋