37.11 problem 1129

Internal problem ID [4325]

Book: Ordinary differential equations and their solutions. By George Moseley Murphy. 1960
Section: Various 37
Problem number: 1129.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [[_homogeneous, `class A`], _rational, _dAlembert]

\[ \boxed {\sqrt {\left (a \,x^{2}+y^{2}\right ) \left (1+{y^{\prime }}^{2}\right )}-y y^{\prime }=x a} \]

Solution by Maple

Time used: 1.156 (sec). Leaf size: 180

dsolve(((a*x^2+y(x)^2)*(1+diff(y(x),x)^2))^(1/2)-y(x)*diff(y(x),x)-a*x = 0,y(x), singsol=all)
 

\begin{align*} y \left (x \right ) = \sqrt {-a}\, x y \left (x \right ) = -\sqrt {-a}\, x y \left (x \right ) = \frac {-x^{-\frac {-a +\sqrt {\left (a -1\right ) a}}{a}} a^{3}+x^{\frac {a +\sqrt {\left (a -1\right ) a}}{a}} c_{1}^{2}+x^{-\frac {-a +\sqrt {\left (a -1\right ) a}}{a}} a^{2}}{2 c_{1} \sqrt {\left (a -1\right ) a}} y \left (x \right ) = -\frac {x^{\frac {a +\sqrt {\left (a -1\right ) a}}{a}} a^{3}-x^{\frac {a +\sqrt {\left (a -1\right ) a}}{a}} a^{2}-x^{-\frac {-a +\sqrt {\left (a -1\right ) a}}{a}} c_{1}^{2}}{2 \sqrt {\left (a -1\right ) a}\, c_{1}} \end{align*}

Solution by Mathematica

Time used: 0.701 (sec). Leaf size: 241

DSolve[((a x^2+y[x]^2)(1+(y'[x])^2))^(1/2) -y[x] y'[x]-a x==0,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \frac {1}{2} \sqrt {a} e^{-c_1} x^{1-\sqrt {\frac {a-1}{a}}} \left (x^{2 \sqrt {\frac {a-1}{a}}}-e^{2 c_1}\right ) y(x)\to \frac {1}{2} \sqrt {a} e^{-c_1} x^{1-\sqrt {\frac {a-1}{a}}} \left (-x^{2 \sqrt {\frac {a-1}{a}}}+e^{2 c_1}\right ) y(x)\to -\frac {1}{2} \sqrt {a} e^{-c_1} x^{1-\sqrt {\frac {a-1}{a}}} \left (-1+e^{2 c_1} x^{2 \sqrt {\frac {a-1}{a}}}\right ) y(x)\to \frac {1}{2} \sqrt {a} e^{-c_1} x^{1-\sqrt {\frac {a-1}{a}}} \left (-1+e^{2 c_1} x^{2 \sqrt {\frac {a-1}{a}}}\right ) \end{align*}