1.391 problem 392

Internal problem ID [8728]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 392.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [[_1st_order, `_with_symmetry_[F(x),G(y)]`]]

\[ \boxed {{y^{\prime }}^{2}-x y^{\prime } y+y^{2} \ln \left (a y\right )=0} \]

Solution by Maple

Time used: 0.172 (sec). Leaf size: 43

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

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

Solution by Mathematica

Time used: 0.317 (sec). Leaf size: 30

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

\begin{align*} y(x)\to \frac {e^{\frac {1}{4} c_1 (2 x-c_1)}}{a} \\ y(x)\to 0 \\ \end{align*}