12.3 problem 3

Internal problem ID [260]

Book: Differential equations and linear algebra, 3rd ed., Edwards and Penney
Section: Section 5.6, Forced Oscillations and Resonance. Page 362
Problem number: 3.
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _linear, _nonhomogeneous]]

\[ \boxed {x^{\prime \prime }+100 x=225 \cos \left (5 t \right )+300 \sin \left (5 t \right )} \] With initial conditions \begin {align*} [x \left (0\right ) = 375, x^{\prime }\left (0\right ) = 0] \end {align*}

Solution by Maple

Time used: 0.031 (sec). Leaf size: 29

dsolve([diff(x(t),t$2)+100*x(t)=225*cos(5*t)+300*sin(5*t),x(0) = 375, D(x)(0) = 0],x(t), singsol=all)
 

\[ x \left (t \right ) = -2 \sin \left (10 t \right )+372 \cos \left (10 t \right )+3 \cos \left (5 t \right )+4 \sin \left (5 t \right ) \]

Solution by Mathematica

Time used: 0.022 (sec). Leaf size: 30

DSolve[{x''[t]+100*x[t]==225*Cos[5*t]+300*Sin[5*t],{x[0]==375,x'[0]==0}},x[t],t,IncludeSingularSolutions -> True]
 

\[ x(t)\to 4 \sin (5 t)-2 \sin (10 t)+3 \cos (5 t)+372 \cos (10 t) \]