[[_2nd_order, _missing_x]]
Book solution method
TO DO
Mathematica ✓
cpu = 1.11781 (sec), leaf count = 37
Maple ✓
cpu = 0.091 (sec), leaf count = 24
DSolve[f[y'[x], y''[x]] == 0,y[x],x]
Mathematica raw output
{{y[x] -> C[2] + Integrate[InverseFunction[Integrate[InverseFunction[f, 2, 2][K[
1], 0]^(-1), {K[1], 1, #1}] & ][C[1] + K[2]], {K[2], 1, x}]}}
Maple raw input
dsolve(f(diff(y(x),x),diff(diff(y(x),x),x)) = 0, y(x),'implicit')
Maple raw output
y(x) = Int(RootOf(x-Intat(1/RootOf(f(_f,_Z)),_f = _Z)+_C1),x)+_C2