2.15 problem Problem 15.33

Internal problem ID [2527]
Internal file name [OUTPUT/2019_Sunday_June_05_2022_02_44_52_AM_32039854/index.tex]

Book: Mathematical methods for physics and engineering, Riley, Hobson, Bence, second edition, 2002
Section: Chapter 15, Higher order ordinary differential equations. 15.4 Exercises, page 523
Problem number: Problem 15.33.
ODE order: 3.
ODE degree: 1.

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

Maple gives the following as the ode type

[[_3rd_order, _exact, _nonlinear]]

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 
-> Calling odsolve with the ODE`, (diff(_b(_a), _a))^2+(diff(_b(_a), _a))*_b(_a)+(diff(diff(_b(_a), _a), _a))*_b(_a)+(1/2)*cos(_a)+c 
   Methods for second order ODEs: 
   --- Trying classification methods --- 
   trying 2nd order Liouville 
   trying 2nd order WeierstrassP 
   trying 2nd order JacobiSN 
   differential order: 2; trying a linearization to 3rd order 
   trying 2nd order ODE linearizable_by_differentiation 
   trying 2nd order, 2 integrating factors of the form mu(x,y) 
   trying a quadrature 
   checking if the LODE has constant coefficients 
   <- constant coefficients successful 
   <- 2nd order, 2 integrating factors of the form mu(x,y) successful 
<- differential order: 3; exact nonlinear successful`
 

Solution by Maple

Time used: 0.015 (sec). Leaf size: 81

dsolve(2*y(x)*diff(y(x),x$3)+2*(y(x)+3*diff(y(x),x))*diff(y(x),x$2)+2*(diff(y(x),x))^2=sin(x),y(x), singsol=all)
 

\begin{align*} y \left (x \right ) &= -\frac {\sqrt {2}\, \sqrt {-4 \left (\left (-\frac {\cos \left (x \right )}{4}+\frac {\sin \left (x \right )}{4}+c_{1} \left (x -1\right )+c_{3} \right ) {\mathrm e}^{x}-c_{2} \right ) {\mathrm e}^{x}}\, {\mathrm e}^{-x}}{2} \\ y \left (x \right ) &= \frac {\sqrt {2}\, \sqrt {-4 \left (\left (-\frac {\cos \left (x \right )}{4}+\frac {\sin \left (x \right )}{4}+c_{1} \left (x -1\right )+c_{3} \right ) {\mathrm e}^{x}-c_{2} \right ) {\mathrm e}^{x}}\, {\mathrm e}^{-x}}{2} \\ \end{align*}

Solution by Mathematica

Time used: 0.473 (sec). Leaf size: 88

DSolve[2*y[x]*y'''[x]+2*(y[x]+3*y'[x])*y''[x]+2*(y'[x])^2==Sin[x],y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to -\frac {\sqrt {-\sin (x)+\cos (x)+2 c_1 x+2 c_3 e^{-x}-2 c_1-4 c_2}}{\sqrt {2}} \\ y(x)\to \frac {\sqrt {-\sin (x)+\cos (x)+2 c_1 x+2 c_3 e^{-x}-2 c_1-4 c_2}}{\sqrt {2}} \\ \end{align*}