6.21 problem 21

Internal problem ID [588]

Book: Elementary differential equations and boundary value problems, 10th ed., Boyce and DiPrima
Section: Miscellaneous problems, end of chapter 2. Page 133
Problem number: 21.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_rational]

\[ \boxed {\frac {-4+6 y x +2 y^{2}}{3 x^{2}+4 y x +3 y^{2}}+y^{\prime }=0} \]

Solution by Maple

Time used: 0.015 (sec). Leaf size: 517

dsolve((-4+6*x*y(x)+2*y(x)^2)/(3*x^2+4*x*y(x)+3*y(x)^2)+diff(y(x),x)=0,y(x), singsol=all)
 

\begin{align*} y \left (x \right ) &= \frac {\left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {1}{3}}}{6}-\frac {10 x^{2}}{3 \left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {1}{3}}}-\frac {2 x}{3} \\ y \left (x \right ) &= -\frac {\left (1+i \sqrt {3}\right ) \left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {1}{3}}}{12}-\frac {5 x \left (i \sqrt {3}\, x -x +\frac {2 \left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {1}{3}}}{5}\right )}{3 \left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {1}{3}}} \\ y \left (x \right ) &= \frac {i \left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {2}{3}} \sqrt {3}+20 i \sqrt {3}\, x^{2}-\left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {2}{3}}-8 x \left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {1}{3}}+20 x^{2}}{12 \left (152 x^{3}-108 c_{1} +432 x +12 \sqrt {216 x^{6}-228 c_{1} x^{3}+912 x^{4}+81 c_{1}^{2}-648 c_{1} x +1296 x^{2}}\right )^{\frac {1}{3}}} \\ \end{align*}

Solution by Mathematica

Time used: 4.748 (sec). Leaf size: 383

DSolve[(-4+6*x*y[x]+2*y[x]^2)/(3*x^2+4*x*y[x]+3*y[x]^2)+y'[x]==0,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \frac {1}{6} \left (2^{2/3} \sqrt [3]{38 x^3+\sqrt {500 x^6+\left (38 x^3+108 x+27 c_1\right ){}^2}+108 x+27 c_1}-\frac {10 \sqrt [3]{2} x^2}{\sqrt [3]{38 x^3+\sqrt {500 x^6+\left (38 x^3+108 x+27 c_1\right ){}^2}+108 x+27 c_1}}-4 x\right ) \\ y(x)\to \frac {1}{12} \left (i 2^{2/3} \left (\sqrt {3}+i\right ) \sqrt [3]{38 x^3+\sqrt {500 x^6+\left (38 x^3+108 x+27 c_1\right ){}^2}+108 x+27 c_1}+\frac {10 \sqrt [3]{2} \left (1+i \sqrt {3}\right ) x^2}{\sqrt [3]{38 x^3+\sqrt {500 x^6+\left (38 x^3+108 x+27 c_1\right ){}^2}+108 x+27 c_1}}-8 x\right ) \\ y(x)\to \frac {1}{12} \left (-2^{2/3} \left (1+i \sqrt {3}\right ) \sqrt [3]{38 x^3+\sqrt {500 x^6+\left (38 x^3+108 x+27 c_1\right ){}^2}+108 x+27 c_1}+\frac {10 \sqrt [3]{2} \left (1-i \sqrt {3}\right ) x^2}{\sqrt [3]{38 x^3+\sqrt {500 x^6+\left (38 x^3+108 x+27 c_1\right ){}^2}+108 x+27 c_1}}-8 x\right ) \\ \end{align*}