A particle moves with its position given by $x = \cos\!\left(t\right)$ and $y = \sin\!\left(\frac{t}{4}\right)$, where positions are given in feet from the origin and time $t$ is in seconds.

Find the speed of the particle.
Speed =
(include units)

Find the first positive time when the particle comes to a stop.
$t =$
(include units)

If $n$ is any odd integer, write a formula (in terms of $n$) for all positive times $t$ at which the particle comes to a stop.
$t =$
(include units)