6.9 problem 9

Internal problem ID [12678]

Book: DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012
Section: Chapter 1. First-Order Differential Equations. Exercises section 1.8 page 121
Problem number: 9.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_linear, `class A`]]

\[ \boxed {y^{\prime }+y=\cos \left (2 t \right )} \] With initial conditions \begin {align*} [y \left (0\right ) = 5] \end {align*}

Solution by Maple

Time used: 0.015 (sec). Leaf size: 23

dsolve([diff(y(t),t)+y(t)=cos(2*t),y(0) = 5],y(t), singsol=all)
 

\[ y \left (t \right ) = \frac {2 \sin \left (2 t \right )}{5}+\frac {\cos \left (2 t \right )}{5}+\frac {24 \,{\mathrm e}^{-t}}{5} \]

Solution by Mathematica

Time used: 0.144 (sec). Leaf size: 27

DSolve[{y'[t]+y[t]==Cos[2*t],{y[0]==5}},y[t],t,IncludeSingularSolutions -> True]
 

\[ y(t)\to \frac {1}{5} \left (24 e^{-t}+2 \sin (2 t)+\cos (2 t)\right ) \]