11.1.1 problem 1

Internal problem ID [1462]
Book : Elementary differential equations and boundary value problems, 11th ed., Boyce, DiPrima, Meade
Section : Chapter 4.1, Higher order linear differential equations. General theory. page 173
Problem number : 1
Date solved : Monday, January 27, 2025 at 04:57:41 AM
CAS classification : [[_high_order, _with_linear_symmetries]]

\begin{align*} y^{\prime \prime \prime \prime }+4 y^{\prime \prime \prime }+3 y&=t \end{align*}

Solution by Maple

Time used: 0.007 (sec). Leaf size: 182

dsolve(diff(y(t),t$4)+4*diff(y(t),t$3)+3*y(t)=t,y(t), singsol=all)
 
\[ y = \frac {t}{3}+{\mathrm e}^{-t} c_1 +c_2 \,{\mathrm e}^{\frac {t \left (\left (-2+\sqrt {2}\right ) \left (4+2 \sqrt {2}\right )^{{2}/{3}}-2 \left (4+2 \sqrt {2}\right )^{{1}/{3}}-2\right )}{2}}+c_3 \,{\mathrm e}^{-\frac {t \left (\left (-2+\sqrt {2}\right ) \left (4+2 \sqrt {2}\right )^{{2}/{3}}-2 \left (4+2 \sqrt {2}\right )^{{1}/{3}}+4\right )}{4}} \cos \left (\frac {\sqrt {3}\, t \left (4+2 \sqrt {2}\right )^{{1}/{3}} \left (2+\left (-2+\sqrt {2}\right ) \left (4+2 \sqrt {2}\right )^{{1}/{3}}\right )}{4}\right )+c_4 \,{\mathrm e}^{-\frac {t \left (\left (-2+\sqrt {2}\right ) \left (4+2 \sqrt {2}\right )^{{2}/{3}}-2 \left (4+2 \sqrt {2}\right )^{{1}/{3}}+4\right )}{4}} \sin \left (\frac {\sqrt {3}\, t \left (4+2 \sqrt {2}\right )^{{1}/{3}} \left (2+\left (-2+\sqrt {2}\right ) \left (4+2 \sqrt {2}\right )^{{1}/{3}}\right )}{4}\right ) \]

Solution by Mathematica

Time used: 0.004 (sec). Leaf size: 100

DSolve[D[y[t],{t,4}]+4*D[ y[t],{t,3}]+3*y[t]==t,y[t],t,IncludeSingularSolutions -> True]
 
\[ y(t)\to c_2 \exp \left (t \text {Root}\left [\text {$\#$1}^3+3 \text {$\#$1}^2-3 \text {$\#$1}+3\&,2\right ]\right )+c_3 \exp \left (t \text {Root}\left [\text {$\#$1}^3+3 \text {$\#$1}^2-3 \text {$\#$1}+3\&,3\right ]\right )+c_1 \exp \left (t \text {Root}\left [\text {$\#$1}^3+3 \text {$\#$1}^2-3 \text {$\#$1}+3\&,1\right ]\right )+\frac {t}{3}+c_4 e^{-t} \]