New estimate on approximations to solutions of the Sturm-Liouville equation by partial sums of asymptotic series (Q1405893)

The author studies the differential equation \[ -y''-q(x)y = \lambda^2y,\quad \lambda>0,\tag{1} \] on the segment \(-a\leq x\leq a\), \(a>0\), with the potential \(q(x)\) analytical in some neighborhood of the segment \([-a,a]\). An approximate fundamental system of solutions to system (1) is constructed by means of partial sums of asymptotic series.