73.24.13 problem 34.6 (c)

Internal problem ID [15693]
Book : Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020
Section : Chapter 34. Power series solutions II: Generalization and theory. Additional Exercises. page 678
Problem number : 34.6 (c)
Date solved : Tuesday, January 28, 2025 at 08:05:26 AM
CAS classification : [_separable]

\begin{align*} y^{\prime }+\cos \left (x \right ) y&=0 \end{align*}

Using series method with expansion around

\begin{align*} 0 \end{align*}

✓ Solution by Maple

Time used: 0.000 (sec). Leaf size: 32

Order:=6; 
dsolve(diff(y(x),x)+cos(x)*y(x)=0,y(x),type='series',x=0);
 

\[ y = \left (1-x +\frac {1}{2} x^{2}-\frac {1}{8} x^{4}+\frac {1}{15} x^{5}\right ) y \left (0\right )+O\left (x^{6}\right ) \]

✓ Solution by Mathematica

Time used: 0.001 (sec). Leaf size: 32

AsymptoticDSolveValue[D[y[x],x]+Cos[x]*y[x]==0,y[x],{x,0,"6"-1}]
 

\[ y(x)\to c_1 \left (\frac {x^5}{15}-\frac {x^4}{8}+\frac {x^2}{2}-x+1\right ) \]