Determine the frequency of y = 2 3 cos 10x. (nearest tenth)
I cannot determine your function, and in fact, I do not see time as a variable.
For y = sin(wx) or y = cos(wx), w = 2pi*f (where f is frequency). So f = w/(2pi).
For y = 3cos(10x), f = 10/(2pi) = 5/pi.