1.545 problem 547

Internal problem ID [8125]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 547.
ODE order: 1.
ODE degree: 4.

CAS Maple gives this as type [[_homogeneous, `class G`]]

\[ \boxed {{y^{\prime }}^{4}-4 y \left (y^{\prime } x -2 y\right )^{2}=0} \]

Solution by Maple

Time used: 0.188 (sec). Leaf size: 122

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

\begin{align*} y \left (x \right ) = \frac {x^{4}}{16} \\ y \left (x \right ) = 0 \\ y \left (x \right ) \left (\sqrt {x^{2}-4 \sqrt {y \left (x \right )}}+x \right )^{\frac {2 \sqrt {y \left (x \right ) x^{2}-4 y \left (x \right )^{\frac {3}{2}}}}{\sqrt {x^{2}-4 \sqrt {y \left (x \right )}}\, \sqrt {y \left (x \right )}}} \left (\sqrt {x^{2}-4 \sqrt {y \left (x \right )}}-x \right )^{-\frac {2 \sqrt {y \left (x \right ) x^{2}-4 y \left (x \right )^{\frac {3}{2}}}}{\sqrt {x^{2}-4 \sqrt {y \left (x \right )}}\, \sqrt {y \left (x \right )}}}-c_{1} = 0 \\ \end{align*}

Solution by Mathematica

Time used: 33.698 (sec). Leaf size: 519

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

\begin{align*} \text {Solve}\left [\frac {\sqrt {\left (x^2+4 \sqrt {y(x)}\right ) y(x)} \log \left (\sqrt {x^2+4 \sqrt {y(x)}}-x\right )}{\sqrt {x^2+4 \sqrt {y(x)}} \sqrt {y(x)}}+\frac {1}{4} \left (\log (y(x))-\frac {\sqrt {x^2+4 \sqrt {y(x)}} \sqrt {y(x)} \log (y(x))}{\sqrt {\left (x^2+4 \sqrt {y(x)}\right ) y(x)}}\right )=c_1,y(x)\right ] \\ \text {Solve}\left [\frac {1}{4} \left (\frac {\sqrt {x^2+4 \sqrt {y(x)}} \sqrt {y(x)} \log (y(x))}{\sqrt {\left (x^2+4 \sqrt {y(x)}\right ) y(x)}}+\log (y(x))\right )-\frac {\sqrt {\left (x^2+4 \sqrt {y(x)}\right ) y(x)} \log \left (\sqrt {x^2+4 \sqrt {y(x)}}-x\right )}{\sqrt {x^2+4 \sqrt {y(x)}} \sqrt {y(x)}}=c_1,y(x)\right ] \\ \text {Solve}\left [\frac {1}{2} \left (\frac {\sqrt {x^2-4 \sqrt {y(x)}} \sqrt {y(x)} \log (y(x))}{2 \sqrt {x^2 y(x)-4 y(x)^{3/2}}}+\frac {1}{2} \log (y(x))\right )-\frac {\sqrt {\left (x^2-4 \sqrt {y(x)}\right ) y(x)} \log \left (\sqrt {x^2-4 \sqrt {y(x)}}-x\right )}{\sqrt {x^2-4 \sqrt {y(x)}} \sqrt {y(x)}}=c_1,y(x)\right ] \\ \text {Solve}\left [\frac {\sqrt {\left (x^2-4 \sqrt {y(x)}\right ) y(x)} \log \left (\sqrt {x^2-4 \sqrt {y(x)}}-x\right )}{\sqrt {x^2-4 \sqrt {y(x)}} \sqrt {y(x)}}+\left (\frac {1}{4}-\frac {\sqrt {x^2 y(x)-4 y(x)^{3/2}}}{4 \sqrt {x^2-4 \sqrt {y(x)}} \sqrt {y(x)}}\right ) \log (y(x))=c_1,y(x)\right ] \\ y(x)\to 0 \\ y(x)\to \frac {x^4}{16} \\ \end{align*}