Given, an=an−1+2 ⇒an−an−1=2 ∴ In this series between any two consecutives terms difference is 2 . So this is an A.P. with common difference 2. Also given a1=1 ∴ Series is =1,3,5,7...... ∴an=1+(n−1)2=2n−1 Also bn=an+bn−1 When n=2 then b2−b1=a2=3 .⇒b2−1=3 [Given b1=1] ⇒b2=4 When n=3 then b3−b2=a3 ⇒b3−4=5 ⇒b3=9 ∴ Series is =1,4,9...... =12,22,32......n2 ∴bn=n2 Now,