Q : 10 Show that form an AP where an is defined as below :
(i)
Also find the sum of the first terms .
It is given that
We will check values of for different values of n
and so on.
From the above, we can clearly see that this is an AP with the first term(a) equals to 7 and common difference (d) equals to 4
Now, we know that
Therefore, the sum of 15 terms is 525