5.9 problem 9

Internal problem ID [5010]
Internal file name [OUTPUT/4503_Sunday_June_05_2022_02_59_39_PM_55860714/index.tex]

Book: Fundamentals of Differential Equations. By Nagle, Saff and Snider. 9th edition. Boston. Pearson 2018.
Section: Chapter 8, Series solutions of differential equations. Section 8.3. page 443
Problem number: 9.
ODE order: 2.
ODE degree: 1.

The type(s) of ODE detected by this program : "second order series method. Irregular singular point"

Maple gives the following as the ode type

[[_2nd_order, _with_linear_symmetries]]

Unable to solve or complete the solution.

\[ \boxed {\sin \left (x \right ) y^{\prime \prime }-y \ln \left (x \right )=0} \] With the expansion point for the power series method at \(x = 0\).

The type of the expansion point is first determined. This is done on the homogeneous part of the ODE. \[ \sin \left (x \right ) y^{\prime \prime }-y \ln \left (x \right ) = 0 \] The following is summary of singularities for the above ode. Writing the ode as \begin {align*} y^{\prime \prime }+p(x) y^{\prime } + q(x) y &=0 \end {align*}

Where \begin {align*} p(x) &= 0\\ q(x) &= -\frac {\ln \left (x \right )}{\sin \left (x \right )}\\ \end {align*}

Table 124: Table \(p(x),q(x)\) singularites.
\(p(x)=0\)
singularity type
\(q(x)=-\frac {\ln \left (x \right )}{\sin \left (x \right )}\)
singularity type
\(x = 0\) \(\text {``irregular''}\)
\(x = \pi Z\) \(\text {``regular''}\)

Combining everything together gives the following summary of singularities for the ode as

Regular singular points : \([\pi Z]\)

Irregular singular points : \([0, \infty ]\)

Since \(x = 0\) is not an ordinary point, then we will now check if it is a regular singular point. Unable to solve since \(x = 0\) is not regular singular point. Terminating.

Verification of solutions N/A

Maple trace

`Methods for second order ODEs: 
--- Trying classification methods --- 
trying a symmetry of the form [xi=0, eta=F(x)] 
checking if the LODE is missing y 
-> Heun: Equivalence to the GHE or one of its 4 confluent cases under a power @ Moebius 
-> trying a solution of the form r0(x) * Y + r1(x) * Y where Y = exp(int(r(x), dx)) * 2F1([a1, a2], [b1], f) 
-> Trying changes of variables to rationalize or make the ODE simpler 
   trying a symmetry of the form [xi=0, eta=F(x)] 
   checking if the LODE is missing y 
   -> Heun: Equivalence to the GHE or one of its 4 confluent cases under a power @ Moebius 
   -> trying a solution of the form r0(x) * Y + r1(x) * Y where Y = exp(int(r(x), dx)) * 2F1([a1, a2], [b1], f) 
      trying a symmetry of the form [xi=0, eta=F(x)] 
      trying 2nd order exact linear 
      trying symmetries linear in x and y(x) 
      trying to convert to a linear ODE with constant coefficients 
      -> trying with_periodic_functions in the coefficients 
         --- Trying Lie symmetry methods, 2nd order --- 
         `, `-> Computing symmetries using: way = 5`[0, u]
 

Solution by Maple

Order:=6; 
dsolve(sin(x)*diff(y(x),x$2)-ln(x)*y(x)=0,y(x),type='series',x=0);
 

\[ \text {No solution found} \]

Solution by Mathematica

Time used: 0.0 (sec). Leaf size: 0

AsymptoticDSolveValue[Sin[x]*y''[x]-Log[x]*y[x]==0,y[x],{x,0,5}]
 

Not solved