I’ve tried like 1000000 times but I cannot find the speed of the particle… plz help…

I’ve tried like 1000000 times
but I cannot find the speed of the particle… plz help me plz
(1 point) A particle moves with its position given by x = cos(8t) and y = sin(t), where positions are given in feet from the origin and time t is in seconds. Find the speed of the particle. Speed = (-8sin8t*cos(t)) feet/second (include units) Find the first positive time when the particle comes to a stop. t = pi/2 seconds (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. npi/2 seconds (include units)