Question

if sum of n terms of an AP is 2n²+5 then prove that an=4n+3

Answer 1

a1=2 (1)^2+5(1)=7

s2=2 (2)^2+5(2)=18

a2=s2-a1=18-7=11

an= (7)+(n-1)4=4n+3

your question is wrong

Sum of n terms=2n^2+5n