11.27 problem 27

Internal problem ID [2166]

Book: Differential Equations by Alfred L. Nelson, Karl W. Folley, Max Coral. 3rd ed. DC heath. Boston. 1964
Section: Exercise 19, page 86
Problem number: 27.
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _with_linear_symmetries]]

\[ \boxed {y^{\prime \prime }-5 y^{\prime }-6 y={\mathrm e}^{3 x}} \] With initial conditions \begin {align*} [y \left (0\right ) = 2, y^{\prime }\left (0\right ) = 1] \end {align*}

Solution by Maple

Time used: 0.015 (sec). Leaf size: 23

dsolve([diff(y(x),x$2)-5*diff(y(x),x)-6*y(x)=exp(3*x),y(0) = 2, D(y)(0) = 1],y(x), singsol=all)
 

\[ y \left (x \right ) = \frac {10 \,{\mathrm e}^{6 x}}{21}+\frac {45 \,{\mathrm e}^{-x}}{28}-\frac {{\mathrm e}^{3 x}}{12} \]

Solution by Mathematica

Time used: 0.045 (sec). Leaf size: 30

DSolve[{y''[x]-5*y'[x]-6*y[x]==Exp[3*x],{y[0]==2,y'[0]==1}},y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to \frac {1}{84} e^{-x} \left (-7 e^{4 x}+40 e^{7 x}+135\right ) \]