1.119 problem 120

1.119.1 Maple step by step solution

Internal problem ID [8456]
Internal file name [OUTPUT/7389_Sunday_June_05_2022_10_54_15_PM_94109174/index.tex]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 120.
ODE order: 1.
ODE degree: 1.

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

Maple gives the following as the ode type

[[_1st_order, `_with_symmetry_[F(x),G(y)]`]]

Unable to solve or complete the solution.

\[ \boxed {x y^{\prime }-y \left (x \ln \left (\frac {x^{2}}{y}\right )+2\right )=0} \] Unable to determine ODE type.

1.119.1 Maple step by step solution

\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & x y^{\prime }-y \left (x \ln \left (\frac {x^{2}}{y}\right )+2\right )=0 \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=\frac {y \left (x \ln \left (\frac {x^{2}}{y}\right )+2\right )}{x} \end {array} \]

Maple trace

`Methods for first order ODEs: 
--- Trying classification methods --- 
trying a quadrature 
trying 1st order linear 
trying Bernoulli 
trying separable 
trying inverse linear 
trying homogeneous types: 
trying Chini 
differential order: 1; looking for linear symmetries 
trying exact 
Looking for potential symmetries 
trying inverse_Riccati 
trying an equivalence to an Abel ODE 
differential order: 1; trying a linearization to 2nd order 
--- trying a change of variables {x -> y(x), y(x) -> x} 
differential order: 1; trying a linearization to 2nd order 
trying 1st order ODE linearizable_by_differentiation 
--- Trying Lie symmetry methods, 1st order --- 
`, `-> Computing symmetries using: way = 3 
`, `-> Computing symmetries using: way = 4`[1, 2*y/x]
 

Solution by Maple

Time used: 0.016 (sec). Leaf size: 16

dsolve(x*diff(y(x),x) - y(x)*(x*ln(x^2/y(x))+2)=0,y(x), singsol=all)
 

\[ y \left (x \right ) = x^{2} {\mathrm e}^{-{\mathrm e}^{-x} c_{1}} \]

Solution by Mathematica

Time used: 0.25 (sec). Leaf size: 20

DSolve[x*y'[x] - y[x]*(x*Log[x^2/y[x]]+2)==0,y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to x^2 e^{-2 c_1 e^{-x}} \]