ecuació diferencial

x^{2}·d_{xx}^{2}[y(x)]+x·d_{x}[y(x)] = m^{2}·y(x)

y(x) = x^{m}

x^{2}·d_{xx}^{2}[y(x)]+x·d_{x}[y(x)] = ∑ c_{n}·x^{n}

y(x) = ∑ ( c_{n}·( 1/(n^{2}) )·x^{n} )