Let P(z) and P(z) be polynomials of the same degree.We consider the equations u''= P(z)u and u''=P(z)u(z∈C) whose solutions are u(z) and u(z),respectively.Let z k(u) and z k(u),k =1,2,···,be the zeros of u(z) and u(z),respectively.We derive bounds for the quantitysup infjk[1/zk(u)-1/zj(u).
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