Find solutions for y" + y = 3 sin(x)
Medal for showing me HOW to get solutions. :)

I think it is 3x sin(x) - 7x cosx
and
y = (3/2)x sin(x)

I still can give a medal! Just want to be correct thanks! :)

Question

Find solutions for y" + y = 3 sin(x)
Medal for showing me HOW to get solutions. :)

I think it is 3x sin(x) - 7x cosx
and
y = (3/2)x sin(x)

I still can give a medal! Just want to be correct thanks! :)

kinggeorge · Answer

So I'm still trying to remember all the details of how to do this, but I do remember that the first step is finding solutions for$$y''+y=0.$$Do you remember how to do that?

anonymous · Answer

then try y = Asinx + Bcosx

kinggeorge · Answer

Ah yes. That was it. Thanks @xxferrocixx. Simply plug in $$y=A\sin(x)+B\cos(x),$$solve for $A$ and $B$, and you're basically done.