The radial oscillation of entire solutions of complex differential equations

This paper is devoted to studying the radial oscillation of solutions of linear differential equations f″+A(z)f′+B(z)f=F(z)f″+A(z)f′+B(z)f=F(z), where A(z)A(z), B(z)B(z) and F(z)F(z) are transcendental entire functions. With some added conditions on coefficients, we show that there exists some close relation between the Borel directions of solutions and that of F(z)F(z), and also obtain some estimates of growth of solutions in the angular domains.