1.448 problem 450

Internal problem ID [8785]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 450.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [[_1st_order, `_with_symmetry_[F(x),G(y)]`]]

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

Solution by Maple

Time used: 0.891 (sec). Leaf size: 51

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

\begin{align*} y \left (x \right ) &= \sqrt {a^{2}-x^{2}} \\ y \left (x \right ) &= -\sqrt {a^{2}-x^{2}} \\ y \left (x \right ) &= c_{1} x^{2}-a^{2} c_{1} -\frac {1}{4 c_{1}} \\ \end{align*}

Solution by Mathematica

Time used: 0.413 (sec). Leaf size: 67

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

\begin{align*} y(x)\to \frac {a^2-x^2+c_1{}^2}{2 c_1} \\ y(x)\to \text {Indeterminate} \\ y(x)\to -\sqrt {a^2-x^2} \\ y(x)\to \sqrt {a^2-x^2} \\ \end{align*}