On the position of zeros and extrema of oscillatory solutions of second order differential equations
The author studies the position of zeros and extrema of solutions to the nonselfadjoint differential equation \( u'' +a(x)u'+b(x)u=0\). His results are generalizations of well-known theorems on oscillatory solutions to the selfadjoint equation \(u'' +a(x)u=0\) [\textit{P. Hartman}, Ordinary differential equations, John Wiley \& Sons, Inc., New York etc. (1964; Zbl 0125.32102) and \textit{A. Laforgia}, Indagationes Math. 44, 295-301 (1982; Zbl 0512.34018)].
scientific article; zbMATH DE number 1014348