What are the cycles per second in the simple harmonic motion described by d=8 cos (pi/2)t? what is the time per second, required per cycle?

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

Which function has the domain x> -11?

Aroulette wheel has 38 slots in which the ball can land. two of the slots are green, 18 are red, and 18 are black. the ball is equally likely to land in any slot. the roulette wheel is going to be spun twice, and the outcomes of the two spins are independent.the probability that it lands one time on red and another time on black in any order is(a) 0.5 (b) 0.25 (c) 0.4488 (d) 0.2244