Question

Sum of the n terms of an A.P. is Sn, sum of 2n terms
is S2n, and the sum of 3n terms is S3n. Prove that:
S3n/Sn= 6, where S2n = 3Sn​

Answer 1

Answer:

Sn=Sn

Sn=a1

we know that when n is not given we have to take n=1

S2 = 3s

a2= s2-s1

a2=3s1-s1

a2= 2s1

a3= 3s1

s3=a1+ a2+ a3

s3/s1 = s1+ 2s1+3s1/ s1

6s1/s1 = 6 ans.

hence proved