[[_3rd_order, _missing_x]]
Book solution method
TO DO
Mathematica ✓
cpu = 0.009094 (sec), leaf count = 84
Maple ✓
cpu = 0.02 (sec), leaf count = 542
DSolve[a3*y[x] + a2*y'[x] + a1*y''[x] + y'''[x] == 0,y[x],x]
Mathematica raw output
{{y[x] -> E^(x*Root[a3 + a2*#1 + a1*#1^2 + #1^3 & , 1])*C[1] + E^(x*Root[a3 + a2
*#1 + a1*#1^2 + #1^3 & , 2])*C[2] + E^(x*Root[a3 + a2*#1 + a1*#1^2 + #1^3 & , 3]
)*C[3]}}
Maple raw input
dsolve(diff(diff(diff(y(x),x),x),x)+a1*diff(diff(y(x),x),x)+a2*diff(y(x),x)+a3*y(x) = 0, y(x),'implicit')
Maple raw output
y(x) = _C3*exp(1/6*((36*a2*a1-108*a3-8*a1^3+12*(81*a3^2+(12*a1^3-54*a1*a2)*a3-3*
a2^2*a1^2+12*a2^3)^(1/2))^(2/3)-2*a1*(36*a2*a1-108*a3-8*a1^3+12*(81*a3^2+(12*a1^
3-54*a1*a2)*a3-3*a2^2*a1^2+12*a2^3)^(1/2))^(1/3)+4*a1^2-12*a2)/(36*a2*a1-108*a3-
8*a1^3+12*(81*a3^2+(12*a1^3-54*a1*a2)*a3-3*a2^2*a1^2+12*a2^3)^(1/2))^(1/3)*x)+_C
2*exp(-1/3*((-1/4*I*3^(1/2)+1/4)*(36*a2*a1-108*a3-8*a1^3+12*(81*a3^2+(12*a1^3-54
*a1*a2)*a3-3*a2^2*a1^2+12*a2^3)^(1/2))^(2/3)+a1*(36*a2*a1-108*a3-8*a1^3+12*(81*a
3^2+(12*a1^3-54*a1*a2)*a3-3*a2^2*a1^2+12*a2^3)^(1/2))^(1/3)+(a1^2-3*a2)*(I*3^(1/
2)+1))*x/(36*a2*a1-108*a3-8*a1^3+12*(81*a3^2+(12*a1^3-54*a1*a2)*a3-3*a2^2*a1^2+1
2*a2^3)^(1/2))^(1/3))+_C1*exp(1/3*((-1/4*I*3^(1/2)-1/4)*(36*a2*a1-108*a3-8*a1^3+
12*(81*a3^2+(12*a1^3-54*a1*a2)*a3-3*a2^2*a1^2+12*a2^3)^(1/2))^(2/3)-a1*(36*a2*a1
-108*a3-8*a1^3+12*(81*a3^2+(12*a1^3-54*a1*a2)*a3-3*a2^2*a1^2+12*a2^3)^(1/2))^(1/
3)+(a1^2-3*a2)*(I*3^(1/2)-1))*x/(36*a2*a1-108*a3-8*a1^3+12*(81*a3^2+(12*a1^3-54*
a1*a2)*a3-3*a2^2*a1^2+12*a2^3)^(1/2))^(1/3))