Question

Find the sum of the n th term of 8,98,998,9998 in term of n​

Answer 1

Answer:

Prove that the sum Sn of n terms of an Arithmetic Progress (A.P.) whose first term ‘a’ and common difference ‘d’ is

S = n2[2a + (n - 1)d]

Or, S = n2[a + l], where l = last term = a + (n - 1)d