Question

For an A.P. Sn=2n²+n then find t2=? 1)3 2)7 3)2 4)8

Answer 1

S1=t1=2×(1^2)+(1)=3.

S2=t1+t2=2×(2^2)+(2)=10.

t2=10-t1=10-3=7.

Option 2) 7 should be the right answer