Sn = [n2(n+1)2] /4

ii.	Sn	=	n2(n+1)2
			4
Sol.	Sn	=	n2(n+1)2
			4
∴	S1	=	12(1+1)2	=	1(2)2	=	1×4	=	4	=	1
			4		4		4		4
∴	S2	=	22(2+1)2	=	4(3)2	=	4×9	=	36	=	9
			4		4		4		4
∴	S3	=	32(3+1)2	=	9(4)2	=	9×16	=	9×4	=	36
			4		4		4

We know that,

t₁ = S₁ = 1

t₂ = S₂ – S₁ = 9 – 1 = 8

t₃ = S₃ – S₂ = 36 – 9 = 27

∴ The first three terms of the sequence are 1, 8 and 27.