8.14 problem 212

Internal problem ID [15100]

Book: A book of problems in ordinary differential equations. M.L. KRASNOV, A.L. KISELYOV, G.I. MARKARENKO. MIR, MOSCOW. 1983
Section: Section 8. First order not solved for the derivative. Exercises page 67
Problem number: 212.
ODE order: 1.
ODE degree: 0.

CAS Maple gives this as type [_quadrature]

\[ \boxed {y-y^{\prime } \ln \left (y^{\prime }\right )=0} \]

Solution by Maple

Time used: 0.0 (sec). Leaf size: 63

dsolve(y(x)=diff(y(x),x)*ln(diff(y(x),x)),y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 4.166 (sec). Leaf size: 83

DSolve[y[x]==y'[x]*Log[y'[x]],y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to -e^{-1-\sqrt {2 x+1+2 c_1}} \left (1+\sqrt {2 x+1+2 c_1}\right ) \\ y(x)\to e^{-1+\sqrt {2 x+1+2 c_1}} \left (-1+\sqrt {2 x+1+2 c_1}\right ) \\ y(x)\to 0 \\ \end{align*}