1.78 problem 81

Internal problem ID [2714]

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: 81.
ODE order: 1.
ODE degree: 3.

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

Solve \begin {gather*} \boxed {y-y^{\prime } x -\left (y^{\prime }\right )^{3}=0} \end {gather*}

Solution by Maple

Time used: 0.187 (sec). Leaf size: 19

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

\begin{align*} y \relax (x ) = c_{1}^{3}+c_{1} x \\ y \relax (x ) = c_{1} x^{\frac {3}{2}} \\ \end{align*}

Solution by Mathematica

Time used: 0.008 (sec). Leaf size: 54

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

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