4.26 problem Recognizable Exact Differential equations. Integrating factors. Exercise 10.18, page 90

Internal problem ID [3985]

Book: Ordinary Differential Equations, By Tenenbaum and Pollard. Dover, NY 1963
Section: Chapter 2. Special types of differential equations of the first kind. Lesson 10
Problem number: Recognizable Exact Differential equations. Integrating factors. Exercise 10.18, page 90.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_exact, _rational, [_1st_order, _with_symmetry_[F(x)*G(y),0]]]

Solve \begin {gather*} \boxed {2 y x +\left (a +x^{2}+y^{2}\right ) y^{\prime }=0} \end {gather*}

Solution by Maple

Time used: 0.016 (sec). Leaf size: 470

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

\begin{align*} y \relax (x ) = \frac {\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}{2}-\frac {2 \left (x^{2}+a \right )}{\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}} \\ y \relax (x ) = -\frac {\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}{4}+\frac {x^{2}+a}{\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}-\frac {i \sqrt {3}\, \left (\frac {\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}{2}+\frac {2 x^{2}+2 a}{\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}\right )}{2} \\ y \relax (x ) = -\frac {\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}{4}+\frac {x^{2}+a}{\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}+\frac {i \sqrt {3}\, \left (\frac {\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}{2}+\frac {2 x^{2}+2 a}{\left (-12 c_{1}+4 \sqrt {4 x^{6}+12 a \,x^{4}+12 a^{2} x^{2}+4 a^{3}+9 c_{1}^{2}}\right )^{\frac {1}{3}}}\right )}{2} \\ \end{align*}

Solution by Mathematica

Time used: 6.033 (sec). Leaf size: 299

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

\begin{align*} y(x)\to \frac {\sqrt [3]{2} \left (\sqrt {4 \left (a+x^2\right )^3+9 c_1{}^2}+3 c_1\right ){}^{2/3}-2 a-2 x^2}{2^{2/3} \sqrt [3]{\sqrt {4 \left (a+x^2\right )^3+9 c_1{}^2}+3 c_1}} \\ y(x)\to \frac {\left (1+i \sqrt {3}\right ) \left (a+x^2\right )}{2^{2/3} \sqrt [3]{\sqrt {4 \left (a+x^2\right )^3+9 c_1{}^2}+3 c_1}}+\frac {i \left (\sqrt {3}+i\right ) \sqrt [3]{\sqrt {4 \left (a+x^2\right )^3+9 c_1{}^2}+3 c_1}}{2 \sqrt [3]{2}} \\ y(x)\to \frac {\left (1-i \sqrt {3}\right ) \left (a+x^2\right )}{2^{2/3} \sqrt [3]{\sqrt {4 \left (a+x^2\right )^3+9 c_1{}^2}+3 c_1}}-\frac {i \left (\sqrt {3}-i\right ) \sqrt [3]{\sqrt {4 \left (a+x^2\right )^3+9 c_1{}^2}+3 c_1}}{2 \sqrt [3]{2}} \\ y(x)\to 0 \\ \end{align*}