ODE
\[ y''''(x)+4 e^{-x} \cos (x)=0 \] ODE Classification
[[_high_order, _quadrature]]
Book solution method
TO DO
Mathematica ✓
cpu = 0.186488 (sec), leaf count = 30
\[\left \{\left \{y(x)\to e^{-x} \cos (x)+x (x (c_4 x+c_3)+c_2)+c_1\right \}\right \}\]
Maple ✓
cpu = 0.391 (sec), leaf count = 28
\[\left [y \left (x \right ) = \frac {x^{2} \textit {\_C2}}{2}+\frac {\textit {\_C1} \,x^{3}}{6}+{\mathrm e}^{-x} \cos \left (x \right )+\textit {\_C3} x +\textit {\_C4}\right ]\] Mathematica raw input
DSolve[(4*Cos[x])/E^x + y''''[x] == 0,y[x],x]
Mathematica raw output
{{y[x] -> C[1] + x*(C[2] + x*(C[3] + x*C[4])) + Cos[x]/E^x}}
Maple raw input
dsolve(diff(diff(diff(diff(y(x),x),x),x),x)+4*exp(-x)*cos(x) = 0, y(x))
Maple raw output
[y(x) = 1/2*x^2*_C2+1/6*_C1*x^3+exp(-x)*cos(x)+_C3*x+_C4]