24.1 problem 3

Internal problem ID [5348]

Book: An introduction to Ordinary Differential Equations. Earl A. Coddington. Dover. NY 1961
Section: Chapter 6. Existence and uniqueness of solutions to systems and nth order equations. Page 250
Problem number: 3.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} y_{1}^{\prime }\relax (x )&=y_{1}\relax (x )\\ y_{2}^{\prime }\relax (x )&=y_{1}\relax (x )+y_{2}\relax (x ) \end {align*}

With initial conditions \[ [y_{1}\relax (0) = 1, y_{2}\relax (0) = 2] \]

Solution by Maple

Time used: 0.058 (sec). Leaf size: 16

dsolve([diff(y__1(x),x) = y__1(x), diff(y__2(x),x) = y__1(x)+y__2(x), y__1(0) = 1, y__2(0) = 2],[y__1(x), y__2(x)], singsol=all)
 

\[ y_{1}\relax (x ) = {\mathrm e}^{x} \] \[ y_{2}\relax (x ) = {\mathrm e}^{x} \left (x +2\right ) \]

Solution by Mathematica

Time used: 0.044 (sec). Leaf size: 18

DSolve[{y1'[x]==y1[x],y2'[x]==y1[x]+y2[x]},{y1[0]==1,y2[0]==2},{y1[x],y2[x]},x,IncludeSingularSolutions -> True]
 

\begin{align*} \text {y1}(x)\to e^x \\ \text {y2}(x)\to e^x (x+2) \\ \end{align*}