2.11 problem 11

Internal problem ID [489]

Book: Elementary differential equations and boundary value problems, 10th ed., Boyce and DiPrima
Section: Section 2.2. Page 48
Problem number: 11.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

Solve \begin {gather*} \boxed {x +y y^{\prime } {\mathrm e}^{-x}=0} \end {gather*} With initial conditions \begin {align*} [y \relax (0) = 1] \end {align*}

Solution by Maple

Time used: 0.046 (sec). Leaf size: 17

dsolve([x+y(x)*diff(y(x),x)/exp(x) = 0,y(0) = 1],y(x), singsol=all)
 

\[ y \relax (x ) = \sqrt {-1-2 x \,{\mathrm e}^{x}+2 \,{\mathrm e}^{x}} \]

Solution by Mathematica

Time used: 0.152 (sec). Leaf size: 19

DSolve[{x+y[x]*y'[x]/Exp[x] == 0,y[0]==1},y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \sqrt {-2 e^x (x-1)-1} \\ \end{align*}