1.392 problem 393

Internal problem ID [7972]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 393.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [_separable]

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

Solution by Maple

Time used: 0.063 (sec). Leaf size: 61

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

\begin{align*} y \left (x \right ) = 0 \\ y \left (x \right ) = \frac {c_{1} \left (\tan \left (x \right )^{2}+1\right ) \sqrt {\frac {\tan \left (x \right )^{2}}{\tan \left (x \right )^{2}+1}}}{\left (1+\sqrt {\tan \left (x \right )^{2}+1}\right ) \tan \left (x \right )} \\ y \left (x \right ) = \frac {c_{1} {\mathrm e}^{\operatorname {arctanh}\left (\frac {1}{\sqrt {\tan \left (x \right )^{2}+1}}\right )} \sqrt {\tan \left (x \right )^{2}+1}}{\tan \left (x \right )} \\ \end{align*}

Solution by Mathematica

Time used: 0.173 (sec). Leaf size: 36

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

\begin{align*} y(x)\to c_1 \csc ^2\left (\frac {x}{2}\right ) \\ y(x)\to c_1 \sec ^2\left (\frac {x}{2}\right ) \\ y(x)\to 0 \\ \end{align*}