73.22.8 problem 31.7 (a)

Internal problem ID [15556]
Book : Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020
Section : Chapter 31. Delta Functions. Additional Exercises. page 572
Problem number : 31.7 (a)
Date solved : Thursday, March 13, 2025 at 06:11:26 AM
CAS classification : [[_linear, `class A`]]

\begin{align*} y^{\prime }+3 y&=\delta \left (t -2\right ) \end{align*}

Using Laplace method With initial conditions

\begin{align*} y \left (0\right )&=2 \end{align*}

✓ Maple. Time used: 8.073 (sec). Leaf size: 22

ode:=diff(y(t),t)+3*y(t) = Dirac(t-2); 
ic:=y(0) = 2; 
dsolve([ode,ic],y(t),method='laplace');
 

\[ y = \operatorname {Heaviside}\left (t -2\right ) {\mathrm e}^{-3 t +6}+2 \,{\mathrm e}^{-3 t} \]

✓ Mathematica. Time used: 0.028 (sec). Leaf size: 29

ode=D[y[t],t]+3*y[t]==DiracDelta[t-2]; 
ic={y[0]==2}; 
DSolve[{ode,ic},y[t],t,IncludeSingularSolutions->True]
 

\[ y(t)\to e^{-3 t} \left (\int _0^te^6 \delta (K[1]-2)dK[1]+2\right ) \]

✓ Sympy. Time used: 0.736 (sec). Leaf size: 46

from sympy import * 
t = symbols("t") 
y = Function("y") 
ode = Eq(-Dirac(t - 2) + 3*y(t) + Derivative(y(t), t),0) 
ics = {y(0): 2} 
dsolve(ode,func=y(t),ics=ics)
 

\[ - \int \operatorname {Dirac}{\left (t - 2 \right )} e^{3 t}\, dt + 3 \int y{\left (t \right )} e^{3 t}\, dt = - \int \limits ^{0} \operatorname {Dirac}{\left (t - 2 \right )} e^{3 t}\, dt + 3 \int \limits ^{0} y{\left (t \right )} e^{3 t}\, dt \]