ODE
\[ y'''(x)-2 y''(x)-3 y'(x)=0 \] ODE Classification
[[_3rd_order, _missing_x]]
Book solution method
TO DO
Mathematica ✓
cpu = 0.165701 (sec), leaf count = 28
\[\left \{\left \{y(x)\to c_1 \left (-e^{-x}\right )+\frac {1}{3} c_2 e^{3 x}+c_3\right \}\right \}\]
Maple ✓
cpu = 0.014 (sec), leaf count = 18
\[[y \left (x \right ) = \textit {\_C1} +\textit {\_C2} \,{\mathrm e}^{-x}+\textit {\_C3} \,{\mathrm e}^{3 x}]\] Mathematica raw input
DSolve[-3*y'[x] - 2*y''[x] + y'''[x] == 0,y[x],x]
Mathematica raw output
{{y[x] -> -(C[1]/E^x) + (E^(3*x)*C[2])/3 + C[3]}}
Maple raw input
dsolve(diff(diff(diff(y(x),x),x),x)-2*diff(diff(y(x),x),x)-3*diff(y(x),x) = 0, y(x))
Maple raw output
[y(x) = _C1+_C2*exp(-x)+_C3*exp(3*x)]