Question

16. A sequence la) is given by a = n2-1, n = N. Show that it is not an A.P
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Answer 1

Answer:

S=1+2+...+(n−1)+n.

Write it backwards: S=n+(n−1)+...+2+1. Add the two equations, term by term; each term is n+1, so 2S=(n+1)+(n+1)+...+(n+1)=n(n+1).

Divide by 2: S=n(n+

Step-by-step explanation:

Answer 2

If it is n’s square
Then first term is n=1 we have 0
n=2 we have 3
n=3 we have 8
So difference is 3-0=3 and 8-3=5 which are not equal so not in AP