23.8 problem 731

Internal problem ID [15474]
Internal file name [OUTPUT/15475_Friday_May_10_2024_03_32_48_PM_54640770/index.tex]

Book: A book of problems in ordinary differential equations. M.L. KRASNOV, A.L. KISELYOV, G.I. MARKARENKO. MIR, MOSCOW. 1983
Section: Chapter 2 (Higher order ODE’s). Section 18.1 Integration of differential equation in series. Power series. Exercises page 171
Problem number: 731.
ODE order: 2.
ODE degree: 1.

The type(s) of ODE detected by this program : "unknown"

Maple gives the following as the ode type

[NONE]

Unable to solve or complete the solution.

Unable to parse ODE.

Maple trace

`Methods for third order ODEs: 
--- Trying classification methods --- 
trying 3rd order ODE linearizable_by_differentiation 
differential order: 3; trying a linearization to 4th order 
trying differential order: 3; missing variables 
trying differential order: 3; exact nonlinear 
trying 3rd order, integrating factor of the form mu(y) for some mu 
Trying the formal computation of integrating factors depending on any 2 of [x, y, y, y] 
differential order: 3; looking for linear symmetries 
--- Trying Lie symmetry methods, high order --- 
`, `-> Computing symmetries using: way = 3 
`, `-> Computing symmetries using: way = 5`
 

Solution by Maple

Time used: 0.015 (sec). Leaf size: 14

Order:=6; 
dsolve([diff(y(x),x$3)+x*sin(y(x))=0,y(0) = 1/2*Pi, D(y)(0) = 0, (D@@2)(y)(0) = 0],y(x),type='series',x=0);
 

\[ y = \frac {\pi }{2}-\frac {1}{24} x^{4}+\operatorname {O}\left (x^{6}\right ) \]

Solution by Mathematica

Time used: 0.055 (sec). Leaf size: 16

AsymptoticDSolveValue[{y'''[x]+x*Sin[y[x]]==0,{y[0]==Pi/2,y'[0]==0,y''[0]==0}},y[x],{x,0,5}]
 

\[ y(x)\to \frac {\pi }{2}-\frac {x^4}{24} \]