摘要:We have previously formulated a program for deducing the intervals of oscillations in the solutions of ordinary second-order linear homogeneous differential equations. In this work, we demonstrate how the oscillation-detection program can be carried out around the regular singular points x = ± 1 $x=\pm1$ of the Legendre differential equations. The solutions y n ( x ) $y_{n}(x)$ of the Legendre equation are predicted to be oscillatory in x < 1 $ x < 1$ for n ≥ 3 $n\geq3$ and nonoscillatory outside of that interval for all values of n. In contrast, the solutions y n m ( x ) $y_{n}^{m}(x)$ of the associated Legendre equation are predicted to be oscillatory for n ≥ 3 $n\geq3$ and m ≤ n − 2 $m\leq n-2$ only in smaller subintervals x < x ∗ < 1 $ x < x_{*} < 1$ , the sizes of which are determined by n and m. Numerical integrations confirm that such subintervals are distinctly smaller than ( − 1 , + 1 ) $(-1, +1)$ .
关键词:oscillations ; second-order linear differential equations ; analytical theory ; transformations ; Legendre differential equations