5.24 problem 11

Internal problem ID [12974]

Book: DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012
Section: Chapter 1. First-Order Differential Equations. Exercises section 1.6 page 89
Problem number: 11.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_quadrature]

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

Solution by Maple

Time used: 0.125 (sec). Leaf size: 21

dsolve(diff(y(t),t)=y(t)*ln(abs(y(t))),y(t), singsol=all)
 

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

Solution by Mathematica

Time used: 0.321 (sec). Leaf size: 35

DSolve[y'[t]==y[t]*Log[Abs[y[t]]],y[t],t,IncludeSingularSolutions -> True]
 

\begin{align*} y(t)\to \text {InverseFunction}\left [\int _1^{\text {$\#$1}}\frac {1}{K[1] \log (| K[1]| )}dK[1]\&\right ][t+c_1] \\ y(t)\to 1 \\ \end{align*}