If sum of n terms of an A.P. is 3n2+5n and Tm=164, then the value of m is
26
27
28
25
Tm=Sm−Sm−1 ⇒164=3m2+5m−3[3(m−1)2+5((m−1)] 164=3(2m−1)+5×1 6m=162⟹m=27
If the sum of n terms of an A.P. is 3n2 + 5n and Tm = 164 then m = ?
If the sum of n terms of an A.P. is 3n2+5n and Tm= 164, m=?