3.24 problem 1024

Internal problem ID [9357]
Internal file name [OUTPUT/8293_Monday_June_06_2022_02_39_21_AM_84902345/index.tex]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 2, linear second order
Problem number: 1024.
ODE order: 2.
ODE degree: 1.

The type(s) of ODE detected by this program : "unknown"

Maple gives the following as the ode type

[[_2nd_order, _with_linear_symmetries]]

Unable to solve or complete the solution.

\[ \boxed {y^{\prime \prime }-\left (1+2 \tan \left (x \right )^{2}\right ) y=0} \]

Maple trace Kovacic algorithm successful

`Methods for second order ODEs: 
--- Trying classification methods --- 
trying a symmetry of the form [xi=0, eta=F(x)] 
checking if the LODE is missing y 
-> Heun: Equivalence to the GHE or one of its 4 confluent cases under a power @ Moebius 
-> trying a solution of the form r0(x) * Y + r1(x) * Y where Y = exp(int(r(x), dx)) * 2F1([a1, a2], [b1], f) 
-> Trying changes of variables to rationalize or make the ODE simpler 
   trying a quadrature 
   checking if the LODE has constant coefficients 
   checking if the LODE is of Euler type 
   trying a symmetry of the form [xi=0, eta=F(x)] 
   checking if the LODE is missing y 
   -> Trying a Liouvillian solution using Kovacics algorithm 
      A Liouvillian solution exists 
      Reducible group (found an exponential solution) 
      Group is reducible, not completely reducible 
   <- Kovacics algorithm successful 
   Change of variables used: 
      [x = arccos(t)] 
   Linear ODE actually solved: 
      (t^2-2)*u(t)-t^3*diff(u(t),t)+(-t^4+t^2)*diff(diff(u(t),t),t) = 0 
<- change of variables successful`
 

Solution by Maple

Time used: 0.172 (sec). Leaf size: 28

dsolve(diff(diff(y(x),x),x)-(1+2*tan(x)^2)*y(x)=0,y(x), singsol=all)
 

\[ y \left (x \right ) = i \sin \left (x \right ) c_{2} +\sec \left (x \right ) \ln \left (\cos \left (x \right )+i \sin \left (x \right )\right ) c_{2} +c_{1} \sec \left (x \right ) \]

Solution by Mathematica

Time used: 0.501 (sec). Leaf size: 46

DSolve[(-1 - 2*Tan[x]^2)*y[x] + y''[x] == 0,y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to c_2 \sec (x) \arctan \left (\frac {\cos (x)}{\sqrt {\sin ^2(x)}-1}\right )-\frac {1}{2} c_2 \sqrt {\sin ^2(x)}+c_1 \sec (x) \]