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)]`]]

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

Solution by Maple

Time used: 0.375 (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 ) = x^{2} c_{1} -c_{1} a^{2}-\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*}