2.12 problem 12

Internal problem ID [490]

Book: Elementary differential equations and boundary value problems, 10th ed., Boyce and DiPrima
Section: Section 2.2. Page 48
Problem number: 12.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

Solve \begin {gather*} \boxed {r^{\prime }-\frac {r^{2}}{x}=0} \end {gather*} With initial conditions \begin {align*} [r \relax (1) = 2] \end {align*}

Solution by Maple

Time used: 0.015 (sec). Leaf size: 14

dsolve([diff(r(x),x) = r(x)^2/x,r(1) = 2],r(x), singsol=all)
 

\[ r \relax (x ) = -\frac {2}{2 \ln \relax (x )-1} \]

Solution by Mathematica

Time used: 0.132 (sec). Leaf size: 15

DSolve[{r'[x] == r[x]^2/x,r[1]==2},r[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} r(x)\to \frac {2}{1-2 \log (x)} \\ \end{align*}