1.557 problem 558

Internal problem ID [8138]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 558.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [[_homogeneous, class A], _dAlembert]

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

Solution by Maple

Time used: 0.141 (sec). Leaf size: 223

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

\begin{align*} x -\frac {{\mathrm e}^{\frac {\arcsinh \left (\frac {\sqrt {-x^{2} a^{2}+x^{2}+y \relax (x )^{2}}\, a +y \relax (x )}{\left (a^{2}-1\right ) x}\right )}{a}} c_{1}}{\sqrt {\frac {-x^{2} a^{2}+a^{2} y \relax (x )^{2}+2 \sqrt {-x^{2} a^{2}+x^{2}+y \relax (x )^{2}}\, a y \relax (x )+x^{2}+y \relax (x )^{2}}{\left (a^{2}-1\right )^{2} x^{2}}}} = 0 \\ x -\frac {{\mathrm e}^{-\frac {\arcsinh \left (\frac {\sqrt {-x^{2} a^{2}+x^{2}+y \relax (x )^{2}}\, a -y \relax (x )}{\left (a^{2}-1\right ) x}\right )}{a}} c_{1}}{\sqrt {-\frac {x^{2} a^{2}-a^{2} y \relax (x )^{2}+2 \sqrt {-x^{2} a^{2}+x^{2}+y \relax (x )^{2}}\, a y \relax (x )-x^{2}-y \relax (x )^{2}}{\left (a^{2}-1\right )^{2} x^{2}}}} = 0 \\ \end{align*}

Solution by Mathematica

Time used: 0.803 (sec). Leaf size: 283

DSolve[-y[x] + x*y'[x] + a*x*Sqrt[1 + y'[x]^2]==0,y[x],x,IncludeSingularSolutions -> True]
 

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