7.7 problem 4

Internal problem ID [4337]

Book: Mathematical Methods in the Physical Sciences. third edition. Mary L. Boas. John Wiley. 2006
Section: Chapter 8, Ordinary differential equations. Section 7. Other second-Order equations. page 435
Problem number: 4.
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _missing_y], [_2nd_order, _reducible, _mu_y_y1]]

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

Solution by Maple

Time used: 0.11 (sec). Leaf size: 31

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

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

Solution by Mathematica

Time used: 2.204 (sec). Leaf size: 103

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

\begin{align*} y(x)\to c_2-i e^{-c_1} \sqrt {-1+e^{2 c_1} x^2} \\ y(x)\to i e^{-c_1} \sqrt {-1+e^{2 c_1} x^2}+c_2 \\ y(x)\to c_2-i \sqrt {x^2} \\ y(x)\to i \sqrt {x^2}+c_2 \\ \end{align*}