2.91 problem 667

Internal problem ID [8245]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, Additional non-linear first order
Problem number: 667.
ODE order: 1.
ODE degree: 1.

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

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

Solution by Maple

Time used: 0.203 (sec). Leaf size: 83

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

\[ x b +\frac {b \,\operatorname {arctanh}\left (\frac {2 y \left (x \right ) {\mathrm e}^{-x b}-b}{\sqrt {b^{2}+4 b}}\right )}{\sqrt {b^{2}+4 b}}+\ln \left (y \left (x \right ) {\mathrm e}^{-x b}\right )-\frac {\ln \left (-b y \left (x \right ) {\mathrm e}^{-x b}+y \left (x \right )^{2} {\mathrm e}^{-2 x b}-b \right )}{2}-c_{1} = 0 \]

Solution by Mathematica

Time used: 2.821 (sec). Leaf size: 95

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

\[ \text {Solve}\left [\frac {2 \sqrt {\frac {b}{b+4}} \text {arctanh}\left (\frac {\sqrt {\frac {b}{b+4}} \left (2 e^{b x}+y(x)\right )}{y(x)}\right )-\log \left (b e^{b x} \left (e^{b x}+y(x)\right )-y(x)^2\right )+2 \log \left (e^{b x}\right )}{2 b}+\frac {\log (y(x))}{b}=c_1,y(x)\right ] \]