Q8 of 97 Page 185

If the sum of n terms of an A.P. is (pn + qn2), where p and q are constants, find the common difference.

Given,


Sum of n terms of A.P. = pn + qn2


We know,


∴



Comparing the coefficients of n2 on both sides, we obtain



⇒ d = 2q


∴ the common difference of the A.P. is 2q.


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