Differential Equations 2 order and objectives

[layt]

Help pls decide this Differential Equations!I did not coincide with the answer and in some no idea how to do! will be very grateful if you start a proper solution to Us
1) y(4)+2*a2*y''+a4*y= cos(ax)
2) y' = x + 1/y; y(0)=1
3) y' = 2*x + cos(y); y(0) = 0
4) y(x) - λ*(0 to pi)∫(x*sin(t)*y(t)*dt = 0 (find λ and y(x))
5) Parachutist descends on a parachute! Gravity parashyuta F1 = mg, and the force of air resistance F2 = k * v ^ 2, k = const find speed through chute t0 seconds after the shutter and the path traversed by S while!

 

[DryRun]

1. Not clear. Check if you've typed it correctly. Isn't there supposed to be a term in y'? Instead there are 2 terms in y?

2. Express in homogeneous form. You might have to do a translation of axes.