15.20 problem 451

Internal problem ID [15241]

Book: A book of problems in ordinary differential equations. M.L. KRASNOV, A.L. KISELYOV, G.I. MARKARENKO. MIR, MOSCOW. 1983
Section: Chapter 2 (Higher order ODE’s). Section 15.2 Homogeneous differential equations with constant coefficients. Exercises page 121
Problem number: 451.
ODE order: 3.
ODE degree: 1.

CAS Maple gives this as type [[_3rd_order, _missing_x]]

\[ \boxed {y^{\prime \prime \prime }-3 y^{\prime }-2 y=0} \]

Solution by Maple

Time used: 0.0 (sec). Leaf size: 21

dsolve(diff(y(x),x$3)-3*diff(y(x),x)-2*y(x)=0,y(x), singsol=all)
 

\[ y \left (x \right ) = \left (c_{3} x +c_{2} \right ) {\mathrm e}^{-x}+c_{1} {\mathrm e}^{2 x} \]

Solution by Mathematica

Time used: 0.002 (sec). Leaf size: 26

DSolve[y'''[x]-3*y'[x]-2*y[x]==0,y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to e^{-x} \left (c_2 x+c_3 e^{3 x}+c_1\right ) \]