The problem on my hw reads as
$e^{-y}\sin t$ (from the hw he hands out) with just a negative sign on the exponent
instead of
$e^{-ft}y\sin ω t$ where $f$ and $ω$ are real constants; $f$ = friction & $ω$ = frequency. (from the online notes)
Did he make a mistake? or are these two different solvable problems.