1.82 problem 127

Internal problem ID [12498]
Internal file name [OUTPUT/11151_Monday_October_16_2023_09_54_06_PM_81038991/index.tex]

Book: DIFFERENTIAL and INTEGRAL CALCULUS. VOL I. by N. PISKUNOV. MIR PUBLISHERS, Moscow 1969.
Section: Chapter 8. Differential equations. Exercises page 595
Problem number: 127.
ODE order: 2.
ODE degree: 1.

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

Maple gives the following as the ode type

[[_3rd_order, _missing_x], [_3rd_order, _missing_y], [_3rd_order, _with_linear_symmetries], [_3rd_order, _reducible, _mu_y2], [_3rd_order, _reducible, _mu_poly_yn]]

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 
`, `-> Computing symmetries using: way = 3 
-> Calling odsolve with the ODE`, diff(_b(_a), _a) = _b(_a)^2, _b(_a), HINT = [[1, 0], [_a, -_b]]`   *** Sublevel 2 *** 
   symmetry methods on request 
`, `1st order, trying reduction of order with given symmetries:`[1, 0], [_a, -_b]
 

Solution by Maple

Time used: 0.078 (sec). Leaf size: 24

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

\[ y \left (x \right ) = \left (-c_{1} -x \right ) \ln \left (c_{1} +x \right )+\left (c_{2} +1\right ) x +c_{3} +c_{1} \]

Solution by Mathematica

Time used: 0.607 (sec). Leaf size: 24

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

\[ y(x)\to x+c_3 x-(x+c_1) \log (x+c_1)+c_2 \]