14.11 problem 11

Internal problem ID [2212]

Book: Differential Equations by Alfred L. Nelson, Karl W. Folley, Max Coral. 3rd ed. DC heath. Boston. 1964
Section: Exercise 23, page 106
Problem number: 11.
ODE order: 4.
ODE degree: 1.

CAS Maple gives this as type [[_high_order, _linear, _nonhomogeneous]]

\[ \boxed {y^{\prime \prime \prime \prime }+3 y^{\prime \prime }-4 y=4 \,{\mathrm e}^{x}+3 \cos \left (2 x \right )} \]

Solution by Maple

Time used: 0.015 (sec). Leaf size: 49

dsolve(diff(y(x),x$4)+3*diff(y(x),x$2)-4*y(x)=4*exp(x)+3*cos(2*x),y(x), singsol=all)
 

\[ y = \frac {2 x \,{\mathrm e}^{x}}{5}-\frac {9 \,{\mathrm e}^{x}}{25}-\frac {3 \cos \left (2 x \right )}{25}-\frac {3 \sin \left (2 x \right ) x}{20}+c_{1} {\mathrm e}^{x}+c_{2} \cos \left (2 x \right )+c_{3} {\mathrm e}^{-x}+c_{4} \sin \left (2 x \right ) \]

Solution by Mathematica

Time used: 0.17 (sec). Leaf size: 55

DSolve[y''''[x]+3*y''[x]-4*y[x]==4*Exp[x]+3*Cos[x],y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to \frac {2 e^x x}{5}-\frac {9 e^x}{25}-\frac {\cos (x)}{2}+c_3 e^{-x}+c_4 e^x+c_1 \cos (2 x)+c_2 \sin (2 x) \]