74.19.3 problem 3

Internal problem ID [16546]
Book : INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014
Section : Chapter 5. Applications of Higher Order Equations. Exercises 5.1, page 232
Problem number : 3
Date solved : Thursday, March 13, 2025 at 08:17:57 AM
CAS classification : [[_2nd_order, _missing_x]]

\begin{align*} x^{\prime \prime }+64 x&=0 \end{align*}

With initial conditions

\begin{align*} x \left (0\right )&={\frac {3}{4}}\\ x^{\prime }\left (0\right )&=-2 \end{align*}

✓ Maple. Time used: 0.017 (sec). Leaf size: 17

ode:=diff(diff(x(t),t),t)+64*x(t) = 0; 
ic:=x(0) = 3/4, D(x)(0) = -2; 
dsolve([ode,ic],x(t), singsol=all);
 

\[ x \left (t \right ) = -\frac {\sin \left (8 t \right )}{4}+\frac {3 \cos \left (8 t \right )}{4} \]

✓ Mathematica. Time used: 0.017 (sec). Leaf size: 22

ode=D[x[t],{t,2}]+64*x[t]==0; 
ic={x[0]==3/4,Derivative[1][x][0 ]==-2}; 
DSolve[{ode,ic},x[t],t,IncludeSingularSolutions->True]
 

\[ x(t)\to \frac {1}{4} (3 \cos (8 t)-\sin (8 t)) \]

✓ Sympy. Time used: 0.085 (sec). Leaf size: 17

from sympy import * 
t = symbols("t") 
x = Function("x") 
ode = Eq(64*x(t) + Derivative(x(t), (t, 2)),0) 
ics = {x(0): 3/4, Subs(Derivative(x(t), t), t, 0): -2} 
dsolve(ode,func=x(t),ics=ics)
 

\[ x{\left (t \right )} = - \frac {\sin {\left (8 t \right )}}{4} + \frac {3 \cos {\left (8 t \right )}}{4} \]