1.83 problem 86

Internal problem ID [3228]

Book: Differential equations for engineers by Wei-Chau XIE, Cambridge Press 2010
Section: Chapter 2. First-Order and Simple Higher-Order Differential Equations. Page 78
Problem number: 86.
ODE order: 1.
ODE degree: 3.

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

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

Solution by Maple

Time used: 0.219 (sec). Leaf size: 107

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

\begin{align*} y \left (x \right ) = -\frac {2 \,2^{\frac {1}{4}} 3^{\frac {1}{4}} \left (-x^{3}\right )^{\frac {1}{4}}}{3} y \left (x \right ) = \frac {2 \,2^{\frac {1}{4}} 3^{\frac {1}{4}} \left (-x^{3}\right )^{\frac {1}{4}}}{3} y \left (x \right ) = -\frac {2 i 2^{\frac {1}{4}} 3^{\frac {1}{4}} \left (-x^{3}\right )^{\frac {1}{4}}}{3} y \left (x \right ) = \frac {2 i 2^{\frac {1}{4}} 3^{\frac {1}{4}} \left (-x^{3}\right )^{\frac {1}{4}}}{3} y \left (x \right ) = 0 y \left (x \right ) = \sqrt {c_{1}^{3}+2 c_{1} x} y \left (x \right ) = -\sqrt {c_{1}^{3}+2 c_{1} x} \end{align*}

Solution by Mathematica

Time used: 0.147 (sec). Leaf size: 119

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

\begin{align*} y(x)\to -\sqrt {2 c_1 x+c_1{}^3} y(x)\to \sqrt {2 c_1 x+c_1{}^3} y(x)\to (-1-i) \left (\frac {2}{3}\right )^{3/4} x^{3/4} y(x)\to (1-i) \left (\frac {2}{3}\right )^{3/4} x^{3/4} y(x)\to (-1+i) \left (\frac {2}{3}\right )^{3/4} x^{3/4} y(x)\to (1+i) \left (\frac {2}{3}\right )^{3/4} x^{3/4} \end{align*}