5.23 problem 20

Internal problem ID [997]

Book: Elementary differential equations with boundary value problems. William F. Trench. Brooks/Cole 2001
Section: Chapter 2, First order equations. Transformation of Nonlinear Equations into Separable Equations. Section 2.4 Page 68
Problem number: 20.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_homogeneous, `class A`], _rational, _Bernoulli]

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

Solution by Maple

Time used: 0.016 (sec). Leaf size: 30

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

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

Solution by Mathematica

Time used: 0.385 (sec). Leaf size: 38

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

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