I'd really love your help with the following problem. I need to make linearization and then to find a general solution of the accepted equation for the differential equation:
$y''+\sin(2x+\cos(2y'+y))+1-\sin(y+3y')=0$
I usually get a system of two equations, derive them and go on. What should I do in this case? is there a way to turn it into a system of two equation of order one? How it's been done?
Thanks a lot