6.2 problem 11

Internal problem ID [5339]

Book: Schaums Outline. Theory and problems of Differential Equations, 1st edition. Frank Ayres. McGraw Hill 1952
Section: Chapter 10. Singular solutions, Extraneous loci. Supplemetary problems. Page 74
Problem number: 11.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [[_1st_order, _with_linear_symmetries], _rational]

\[ \boxed {y^{2} {y^{\prime }}^{2}+3 x y^{\prime }-y=0} \]

Solution by Maple

Time used: 0.141 (sec). Leaf size: 123

dsolve(y(x)^2*diff(y(x),x)^2+3*x*diff(y(x),x)-y(x)=0,y(x), singsol=all)
 

\begin{align*} y \left (x \right ) &= \frac {18^{\frac {1}{3}} \left (-x^{2}\right )^{\frac {1}{3}}}{2} \\ y \left (x \right ) &= -\frac {2^{\frac {1}{3}} \left (-x^{2}\right )^{\frac {1}{3}} \left (3 i 3^{\frac {1}{6}}+3^{\frac {2}{3}}\right )}{4} \\ y \left (x \right ) &= -\frac {2^{\frac {1}{3}} \left (-x^{2}\right )^{\frac {1}{3}} \left (3^{\frac {2}{3}}-3 i 3^{\frac {1}{6}}\right )}{4} \\ y \left (x \right ) &= 0 \\ y \left (x \right ) &= \operatorname {RootOf}\left (-2 \ln \left (x \right )-3 \left (\int _{}^{\textit {\_Z}}\frac {4 \textit {\_a}^{3}+3 \sqrt {4 \textit {\_a}^{3}+9}+9}{\textit {\_a} \left (4 \textit {\_a}^{3}+9\right )}d \textit {\_a} \right )+2 c_{1} \right ) x^{\frac {2}{3}} \\ \end{align*}

Solution by Mathematica

Time used: 0.597 (sec). Leaf size: 239

DSolve[y[x]^2*y'[x]^2+3*x*y'[x]-y[x]==0,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to e^{\frac {c_1}{3}} \sqrt [3]{-3 x+e^{c_1}} \\ y(x)\to -\sqrt [3]{-1} e^{\frac {c_1}{3}} \sqrt [3]{-3 x+e^{c_1}} \\ y(x)\to (-1)^{2/3} e^{\frac {c_1}{3}} \sqrt [3]{-3 x+e^{c_1}} \\ y(x)\to e^{\frac {c_1}{3}} \sqrt [3]{3 x+e^{c_1}} \\ y(x)\to -\sqrt [3]{-1} e^{\frac {c_1}{3}} \sqrt [3]{3 x+e^{c_1}} \\ y(x)\to (-1)^{2/3} e^{\frac {c_1}{3}} \sqrt [3]{3 x+e^{c_1}} \\ y(x)\to 0 \\ y(x)\to -\left (-\frac {3}{2}\right )^{2/3} x^{2/3} \\ y(x)\to -\left (\frac {3}{2}\right )^{2/3} x^{2/3} \\ y(x)\to \frac {\sqrt [3]{-1} 3^{2/3} x^{2/3}}{2^{2/3}} \\ \end{align*}