4.45.15 y(x)=y(x)+excos(x)

ODE
y(x)=y(x)+excos(x) ODE Classification

[[_high_order, _linear, _nonhomogeneous]]

Book solution method
TO DO

Mathematica
cpu = 0.066143 (sec), leaf count = 38

{{y(x)c1ex+c3ex+c4sin(x)+(c2ex5)cos(x)}}

Maple
cpu = 0.096 (sec), leaf count = 31

{y(x)=_C4ex+(5_C1ex)cos(x)5+_C2ex+_C3sin(x)} Mathematica raw input

DSolve[y''''[x] == E^x*Cos[x] + y[x],y[x],x]

Mathematica raw output

{{y[x] -> E^x*C[1] + C[3]/E^x + (-E^x/5 + C[2])*Cos[x] + C[4]*Sin[x]}}

Maple raw input

dsolve(diff(diff(diff(diff(y(x),x),x),x),x) = y(x)+exp(x)*cos(x), y(x),'implicit')

Maple raw output

y(x) = _C4*exp(-x)+1/5*(5*_C1-exp(x))*cos(x)+_C2*exp(x)+_C3*sin(x)