2.92 problem 668

Internal problem ID [9003]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, Additional non-linear first order
Problem number: 668.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_1st_order, _with_linear_symmetries], [_Abel, `2nd type`, `class C`]]

\[ \boxed {y^{\prime }-\frac {y^{3} {\mathrm e}^{-2 x}}{{\mathrm e}^{-x} y+1}=0} \]

Solution by Maple

Time used: 5.344 (sec). Leaf size: 58

dsolve(diff(y(x),x) = 1/(y(x)*exp(-x)+1)*y(x)^3*exp(-2*x),y(x), singsol=all)
 

\[ y \left (x \right ) = {\mathrm e}^{\operatorname {RootOf}\left (2 \sqrt {5}\, \operatorname {arctanh}\left (\frac {\left (-2 \,{\mathrm e}^{\textit {\_Z}}+{\mathrm e}^{x}\right ) \sqrt {5}\, {\mathrm e}^{-x}}{5}\right )+5 \ln \left ({\mathrm e}^{2 \textit {\_Z}}-{\mathrm e}^{x +\textit {\_Z}}-{\mathrm e}^{2 x}\right )+10 c_{1} -10 \textit {\_Z} -10 x \right )} \]

Solution by Mathematica

Time used: 0.545 (sec). Leaf size: 73

DSolve[y'[x] == y[x]^3/(E^(2*x)*(1 + y[x]/E^x)),y[x],x,IncludeSingularSolutions -> True]
 

\[ \text {Solve}\left [\log (y(x))+\frac {1}{10} \left (-\left (5+\sqrt {5}\right ) \log \left (-\sqrt {5} y(x)+y(x)+2 e^x\right )+\left (\sqrt {5}-5\right ) \log \left (\sqrt {5} y(x)+y(x)+2 e^x\right )+10 \log \left (e^x\right )\right )=c_1,y(x)\right ] \]