EN
We consider the second order self-adjoint differential equation
(1) (r(t)y'(t))' + p(t)y(t) = 0
on an interval I, where r, p are continuous functions and r is positive on I. The aim of this paper is to show one possibility to write equation (1) in the same form but with positive coefficients, say r₁, p₁ and to derive a sufficient condition for equation (1) to be oscillatory in the case p is nonnegative and $∫^∞ [1/r(t)]dt$ converges.