1.458 problem 459

Internal problem ID [8039]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 459.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [[_1st_order, _with_symmetry_[F(x),G(x)*y+H(x)]]]

Solve \begin {gather*} \boxed {{\mathrm e}^{-2 x} \left (y^{\prime }\right )^{2}-\left (y^{\prime }-1\right )^{2}+{\mathrm e}^{-2 y}=0} \end {gather*}

Solution by Maple

Time used: 0.27 (sec). Leaf size: 65

dsolve(exp(-2*x)*diff(y(x),x)^2-(diff(y(x),x)-1)^2+exp(-2*y(x)) = 0,y(x), singsol=all)
 

\begin{align*} y \relax (x ) = x +\ln \left (\left (-1-\sqrt {{\mathrm e}^{2 x}-{\mathrm e}^{-2 c_{1}} {\mathrm e}^{2 x}}\right ) {\mathrm e}^{-x}\right )+c_{1} \\ y \relax (x ) = x +\ln \left (\left (-1+\sqrt {{\mathrm e}^{2 x}-{\mathrm e}^{-2 c_{1}} {\mathrm e}^{2 x}}\right ) {\mathrm e}^{-x}\right )+c_{1} \\ \end{align*}

Solution by Mathematica

Time used: 22.41 (sec). Leaf size: 583

DSolve[E^(-2*y[x]) - (-1 + y'[x])^2 + y'[x]^2/E^(2*x)==0,y[x],x,IncludeSingularSolutions -> True]
 

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