27.5 problem Ex 5

Internal problem ID [10253]

Book: An elementary treatise on differential equations by Abraham Cohen. DC heath publishers. 1906
Section: Chapter VII, Linear differential equations with constant coefficients. Article 50. Method of undetermined coefficients. Page 107
Problem number: Ex 5.
ODE order: 3.
ODE degree: 1.

CAS Maple gives this as type [[_3rd_order, _with_linear_symmetries]]

Solve \begin {gather*} \boxed {y^{\prime \prime \prime }-y-x^{2}=0} \end {gather*}

Solution by Maple

Time used: 0.016 (sec). Leaf size: 40

dsolve(diff(y(x),x$3)-y(x)=x^2,y(x), singsol=all)
 

\[ y \relax (x ) = -x^{2}+c_{1} {\mathrm e}^{x}+c_{2} {\mathrm e}^{-\frac {x}{2}} \cos \left (\frac {\sqrt {3}\, x}{2}\right )+c_{3} {\mathrm e}^{-\frac {x}{2}} \sin \left (\frac {\sqrt {3}\, x}{2}\right ) \]

Solution by Mathematica

Time used: 0.009 (sec). Leaf size: 54

DSolve[y'''[x]-y[x]==x^2,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to -x^2+c_1 e^x+e^{-x/2} \left (c_2 \cos \left (\frac {\sqrt {3} x}{2}\right )+c_3 \sin \left (\frac {\sqrt {3} x}{2}\right )\right ) \\ \end{align*}