Question

@
y''+6y'+73y=80(e^x)cos (4x)
this is a ODE question. how to get the particular solution by complexify the equation?
thanks! @
y''+6y'+73y=80(e^x)cos (4x)
this is a ODE question. how to get the particular solution by complexify the equation?
thanks! @OCW Scholar - Mul…

Answer 1

I believe all you need to do is use the fact that:
\[\cos(4x)=\frac{e^{4ix}+e^{-4ix}}{2}\]
Then your particular solution will only have exponentials.

Answer 2

wrong