1.89 problem 92

Internal problem ID [3234]

Book: Differential equations for engineers by Wei-Chau XIE, Cambridge Press 2010
Section: Chapter 2. First-Order and Simple Higher-Order Differential Equations. Page 78
Problem number: 92.
ODE order: 1.
ODE degree: 0.

CAS Maple gives this as type [[_1st_order, _with_linear_symmetries], _dAlembert]

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

Solution by Maple

Time used: 0.015 (sec). Leaf size: 69

dsolve(2*x*diff(y(x),x) -y(x) = ln(diff(y(x),x)),y(x), singsol=all)
 

\begin{align*} y \left (x \right ) &= 1+\sqrt {4 c_{1} x +1}+\ln \left (2\right )-\ln \left (\frac {1+\sqrt {4 c_{1} x +1}}{x}\right ) \\ y \left (x \right ) &= 1-\sqrt {4 c_{1} x +1}+\ln \left (2\right )-\ln \left (\frac {1-\sqrt {4 c_{1} x +1}}{x}\right ) \\ \end{align*}

Solution by Mathematica

Time used: 0.106 (sec). Leaf size: 34

DSolve[2*x*y'[x] -y[x] == Log[y'[x]],y[x],x,IncludeSingularSolutions -> True]
 

\[ \text {Solve}\left [W\left (-2 x e^{-y(x)}\right )-\log \left (W\left (-2 x e^{-y(x)}\right )+2\right )+y(x)=c_1,y(x)\right ] \]