English: Only thing you have to see is this equation$\ \ r^{2}{R_{n}}^{''}(r) + r{R_{n}}^{'}(r) - \frac{n^{2}\pi^{2}}{\left( \theta_{2} - \theta_{1} \right)^{2}}\ R_{n}(r) = 0$, is now for 0 < r < r₂.
Telugu: మీరు చూడవలసిందల్లా ఈ సమీకరణం$\ \ r^{2}{R_{n}}^{'(r) + r{R_{n}}^{'}(r) - \frac{n^{2}\pi^{2}}{\ఎడమ(\theta_{2} - \theta_{1} \కుడి)^{2}}} R_{n}(r) = 0$, ఇప్పుడు 0 < r <.