On interval 0<=x<2 pi, where are the x-intercepts of y= cos (2x)? A

pi/2 and 3pi/2

B

0, pi, and 2 pi

C

pi/2, pi , and 3pi/2

D

pi/4, 3pi/4, 5 pi/4, and 7pi/4

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days