The Total solution for NCERT class 6-12
If the sum of┬аn┬аterms of an A.P. is (pn┬а+┬аqn2),where┬аp┬аand┬аq┬аare constants, find the commondifference.
We know that,
Sn┬а=n/2 [2a + (n-1)d]
From the question wehave,
On comparing thecoefficients of┬аn2┬аon both sides, we get
d/2 = q
Hence,┬аd┬а=2q
Therefore, the commondifference of the A.P. is 2q.