44.1.4 problem 4

Internal problem ID [6879]
Book : A First Course in Differential Equations with Modeling Applications by Dennis G. Zill. 12 ed. Metric version. 2024. Cengage learning.
Section : Chapter 1. Introduction to differential equations. Exercises 1.1 at page 12
Problem number : 4
Date solved : Monday, January 27, 2025 at 02:32:12 PM
CAS classification : [NONE]

\begin{align*} u^{\prime \prime }+u^{\prime }+u&=\cos \left (r +u\right ) \end{align*}

✗ Solution by Maple

dsolve(diff(u(r),r$2)+diff(u(r),r)+u(r)=cos(r+u(r)),u(r), singsol=all)
 

\[ \text {No solution found} \]

✗ Solution by Mathematica

Time used: 0.000 (sec). Leaf size: 0

DSolve[D[u[r],{r,2}]+D[u[r],r]+u[r]==Cos[r+u[r]],u[r],r,IncludeSingularSolutions -> True]
 

Not solved