Q9 of 167 Page 20

Mark the correct alternative in the following:

If the sum of n terms of an A.P. is 2, then its nth term is


Here, Sn=2n2+5n


∴ S1=2+5=7


∴ a1=S1=7


And S2=2×22+5×2=18


Now,a2=S2-S1=18-7=11


∴ d=a2-a1=11-7=4


Now, an=a1+(n-1)d


=7+(n-1)4


=7+4n-4


=4n+3

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