2.8 problem 8

Internal problem ID [1656]

Book: Differential equations and their applications, 3rd ed., M. Braun
Section: Section 1.2. Page 9
Problem number: 8.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

\[ \boxed {\sqrt {t^{2}+1}\, y+y^{\prime }=0} \] With initial conditions \begin {align*} \left [y \left (0\right ) = \sqrt {5}\right ] \end {align*}

Solution by Maple

Time used: 0.047 (sec). Leaf size: 24

dsolve([(t^2+1)^(1/2)*y(t)+diff(y(t),t) = 0,y(0) = 5^(1/2)],y(t), singsol=all)
 

\[ y \left (t \right ) = \sqrt {5}\, {\mathrm e}^{-\frac {t \sqrt {t^{2}+1}}{2}-\frac {\operatorname {arcsinh}\left (t \right )}{2}} \]

Solution by Mathematica

Time used: 0.088 (sec). Leaf size: 44

DSolve[{(t^2+1)^(1/2)*y[t]+y'[t] == 0,y[0]==Sqrt[5]},y[t],t,IncludeSingularSolutions -> True]
                                                                                    
                                                                                    
 

\[ y(t)\to \sqrt {5} e^{-\frac {1}{2} t \sqrt {t^2+1}} \sqrt {\sqrt {t^2+1}-t} \]