On Petrenko's deviations and second order differential equations

Abstract

New results on the oscillation of solutions of f ″ + A(z)f = 0 and on the growth of solutions of f ″ + A(z)f ′ + B(z)f = 0 are obtained, where A and B are entire functions. Petrenko's magnitudes of deviation of g with respect to ∞ play a key rôle in the results, where g represents one of the coefficients A or B.