Which of the following are identities? check all that apply. a. cos(x + y) + cos(x - y) = 2009 xcosy o b. cos(x + y) - cos(x - y) = 2 coexcosy c. sin(x + y) + sin(x - y) = 2cosxsiny d. tar(x - 25) = tan x

Determine whether the points (–3,–6) and (2,–8) are in the solution set of the system of inequalities below. x ? –3 y < 5? 3x + 2 a. the point (–3,–6) is not in the solution set, and the point (2,–8) is in the solution set. b. neither of the points is in the solution set. c. the point (–3,–6) is in the solution set, and the point (2,–8) is not in the solution set. d. both points are in the solution set.

You were told that the amount of time lapsed between consecutive trades on the new york stock exchange followed a normal distribution with a mean of 15 seconds. you were also told that the probability that the time lapsed between two consecutive trades to fall between 16 to 17 seconds was 13%. the probability that the time lapsed between two consecutive trades would fall below 13 seconds was 7%. what is the probability that the time lapsed between two consecutive trades will be between 14 and 15 seconds?

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply