On the growth of solutions of second order linear complex differential equations whose coefficients satisfy certain conditions

In this paper, we study the growth of solutions of the second order linear complex differential equations f''+A(z)f'+B(z)f=0 insuring that any nontrivial solutions are of infinite order. It is assumed that the coefficients satisfy the extremal condition for Yang’s inequality and the extremal condition for Denjoy’s conjecture. The other condition is that one of the coefficients itself is a solution of the differential equation f''+P(z)f=0.