Solution
= Solution
Regularity at the origin excludes the <natural logarithm> and every negative radial power. Thus
$$
\boxed{c_0=0,\qquad c_n=d_n=0\quad(n\geq1)}.
$$
The coefficients $a_0,a_n,b_n$ remain arbitrary.
= Solution
Regularity at the origin excludes the <natural logarithm> and every negative radial power. Thus
$$
\boxed{c_0=0,\qquad c_n=d_n=0\quad(n\geq1)}.
$$
The coefficients $a_0,a_n,b_n$ remain arbitrary.