Question

which cosine function has maximum of .5 a minimum of -.5 and a period of (2pi/3)?

Is it y= 2cos3(theta) or y=.5cos3(theta)

Answer 1

y = A*cos(Bx) has an amplitude of |A| and a period of 2pi/B

Answer 2

in the first one, A = 2, so the amplitude is |A| = |2| = 2

this means that the max is 2 and the min is -2, which is not what we want

Answer 3

so we can rule that out