9.9 problem 5, using series method

Internal problem ID [4900]

Book: Mathematical Methods in the Physical Sciences. third edition. Mary L. Boas. John Wiley. 2006
Section: Chapter 12, Series Solutions of Differential Equations. Section 1. Miscellaneous problems. page 564
Problem number: 5, using series method.
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _missing_x]]

\[ \boxed {y^{\prime \prime }-y=0} \] With the expansion point for the power series method at \(x = 0\).

Solution by Maple

Time used: 0.0 (sec). Leaf size: 34

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

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

Solution by Mathematica

Time used: 0.001 (sec). Leaf size: 42

AsymptoticDSolveValue[y''[x]==y[x],y[x],{x,0,5}]
 

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