60.1.311 problem 312

Internal problem ID [10325]
Book : Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section : Chapter 1, linear first order
Problem number : 312
Date solved : Tuesday, January 28, 2025 at 04:36:07 PM
CAS classification : [_rational]

\begin{align*} \left (\frac {y^{2}}{b}+\frac {x^{2}}{a}\right ) \left (y^{\prime } y+x \right )+\frac {\left (a -b \right ) \left (y^{\prime } y-x \right )}{a +b}&=0 \end{align*}

Solution by Maple

Time used: 0.009 (sec). Leaf size: 244

dsolve((y(x)^2/b+x^2/a)*(y(x)*diff(y(x),x)+x)+(a-b)/(a+b)*(y(x)*diff(y(x),x)-x) = 0,y(x), singsol=all)
 
\begin{align*} y &= \frac {\sqrt {a \left ({\mathrm e}^{\frac {-2 \operatorname {LambertW}\left (\frac {\left (a +b \right ) {\mathrm e}^{\frac {\left (-x^{2}-b \right ) a^{2}+\left (-b^{2}-2 c_{1} \right ) a +b^{2} x^{2}}{2 a^{2} b}}}{2 a^{2} b}\right ) a^{2} b +\left (-x^{2}-b \right ) a^{2}+\left (-b^{2}-2 c_{1} \right ) a +b^{2} x^{2}}{2 a^{2} b}}+b \left (-x^{2}+a \right )\right )}}{a} \\ y &= -\frac {\sqrt {a \left ({\mathrm e}^{\frac {-2 \operatorname {LambertW}\left (\frac {\left (a +b \right ) {\mathrm e}^{\frac {\left (-x^{2}-b \right ) a^{2}+\left (-b^{2}-2 c_{1} \right ) a +b^{2} x^{2}}{2 a^{2} b}}}{2 a^{2} b}\right ) a^{2} b +\left (-x^{2}-b \right ) a^{2}+\left (-b^{2}-2 c_{1} \right ) a +b^{2} x^{2}}{2 a^{2} b}}+b \left (-x^{2}+a \right )\right )}}{a} \\ \end{align*}

Solution by Mathematica

Time used: 60.949 (sec). Leaf size: 190

DSolve[((a - b)*(-x + y[x]*D[y[x],x]))/(a + b) + (x^2/a + y[x]^2/b)*(x + y[x]*D[y[x],x])==0,y[x],x,IncludeSingularSolutions -> True]
 
\begin{align*} y(x)\to -\frac {\sqrt {b} \sqrt {(a+b) \left (a-x^2\right )+2 a^2 W\left (\frac {c_1 (a+b) e^{-\frac {a^2 \left (b+x^2\right )+a b^2-b^2 x^2}{2 a^2 b}}}{2 a^3 b^2}\right )}}{\sqrt {a} \sqrt {a+b}} \\ y(x)\to \frac {\sqrt {b} \sqrt {(a+b) \left (a-x^2\right )+2 a^2 W\left (\frac {c_1 (a+b) e^{-\frac {a^2 \left (b+x^2\right )+a b^2-b^2 x^2}{2 a^2 b}}}{2 a^3 b^2}\right )}}{\sqrt {a} \sqrt {a+b}} \\ \end{align*}