ODE
\[ y'''(x)+y'(x)=0 \] ODE Classification
[[_3rd_order, _missing_x]]
Book solution method
TO DO
Mathematica ✓
cpu = 0.0163954 (sec), leaf count = 19
\[\left \{\left \{y(x)\to c_1 \sin (x)-c_2 \cos (x)+c_3\right \}\right \}\]
Maple ✓
cpu = 0.006 (sec), leaf count = 14
\[ \left \{ y \left ( x \right ) ={\it \_C1}+{\it \_C2}\,\sin \left ( x \right ) +{\it \_C3}\,\cos \left ( x \right ) \right \} \] Mathematica raw input
DSolve[y'[x] + y'''[x] == 0,y[x],x]
Mathematica raw output
{{y[x] -> C[3] - C[2]*Cos[x] + C[1]*Sin[x]}}
Maple raw input
dsolve(diff(diff(diff(y(x),x),x),x)+diff(y(x),x) = 0, y(x),'implicit')
Maple raw output
y(x) = _C1+_C2*sin(x)+_C3*cos(x)