We have the terms 8,15,24,35
Let us compute 1st order difference 7,9,11 which is an AP
Next difference is 13 and so next term is 35 + 13 = 48
So the nth term of the given sequence is quadratic say an^2+bn + c
Putting n =1 ,n= 2 and n =3 we get following
a+b + c = 8\cdots(1)
4a+2b + c = 15\cdots(2)
9a+3b + c = 24\cdots(3)
Subtracting (1) from (2) we get
3a+b = 7\cdots(4)
Subtracting (2) from (3) we get
5a+b = 9\cdots(5)
Subtracting (4) from (3) we get 2a=2 or a=1
Putting a=1 in (4) we get b=4 and putting in (1) we get c=3
So n^{th} term = n^2+4n + 3
we get the same results by putting n=1,2,3,4 so on
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