This is actually part of a spring question I'm attempting at the moment, and I'm having a mental blank on how to deal with the 3.36.
The Attempt at a Solution
I've found the characteristic equation and solution based from that;
[tex] c_1 cos(4x) + c_2 sin(4x) [/tex]
but the answer is
[tex] c_1 cos(4x) + c_2 sin(4x) + 0.21 [/tex]