6.25 problem 28

Internal problem ID [4535]

Book: Fundamentals of Differential Equations. By Nagle, Saff and Snider. 9th edition. Boston. Pearson 2018.
Section: Chapter 8, Series solutions of differential equations. Section 8.4. page 449
Problem number: 28.
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _linear, _nonhomogeneous]]

Solve \begin {gather*} \boxed {y^{\prime \prime }-\sin \relax (x ) y-\cos \relax (x )=0} \end {gather*} With the expansion point for the power series method at \(x = 0\).

Solution by Maple

Time used: 0.016 (sec). Leaf size: 35

Order:=6; 
dsolve(diff(y(x),x$2)-sin(x)*y(x)=cos(x),y(x),type='series',x=0);
 

\[ y \relax (x ) = \left (1+\frac {1}{6} x^{3}-\frac {1}{120} x^{5}\right ) y \relax (0)+\left (x +\frac {1}{12} x^{4}\right ) D\relax (y )\relax (0)+\frac {x^{2}}{2}-\frac {x^{4}}{24}+\frac {x^{5}}{40}+O\left (x^{6}\right ) \]

Solution by Mathematica

Time used: 0.04 (sec). Leaf size: 56

AsymptoticDSolveValue[y''[x]-Sin[x]*y[x]==Cos[x],y[x],{x,0,5}]
 

\[ y(x)\to \frac {x^5}{40}-\frac {x^4}{24}+c_2 \left (\frac {x^4}{12}+x\right )+\frac {x^2}{2}+c_1 \left (-\frac {x^5}{120}+\frac {x^3}{6}+1\right ) \]