Question

verify :1+2+3+...+n=n (n+1)/2,taking n=12 and 16

Answer 1

A sequence is a function who is domain is the set of the natural numbers of the subset of of it that is sequence is just the arrangement of the members

In progression there of three types

Firstly they are

1. Arithmetic progression

2. Geometric progression

3. Harmonic progression

Answer 2

12(13)/2. 16(17)/2

156/2=78. 272/2=136