if the sum of first m terms of an AP is am2 +bm,find its common differance? Share with your friends Share 2 Manbar Singh answered this It is given that:Sm = am2 + bm∴ S1 = a 12 + b1 = a + bHence, a1 = a + b as a1 = S1Now, S2 = a 22 + b × 2⇒ S2 = 4a + 2bBut a2 = S2 - S1a2 = 4a + 2b - a + ba2 = 4a + 2b - a - ba2 = 3a + b∴ the common difference, d = a2 - a1d = 3a + b - a + bd = 3a + b - a - bd = 2a∴ the common difference is 2a. 11 View Full Answer
