Question

what is the sum of n terms of the series

Answer 1

a=root 2
d= 2root2- root 2=root 2
hence d=root 2
Sn=n/2(2a+(n-1)d)
=n/2(2 root2+n root 2-root 2)
=n/2( root2(1+n))
on solving
=n(n+1)/root2

hence option (c) is correct