function y = 4-2(2t+pi/2), where t is measured in radians.

A.choose one option which gives the value of the function when t=pi radians
B.choose one option which gives the period of the function in radians.

a)0 b)1 c)2 d)4 e)pi/4 f)pi/2 g)pi h)2pi

A, Just plug in pi for t and recompute y

y = 4 - 2[(5/2)pi] = 4 - 5 pi

B. The coefficient of t, which is 4 in this case (ignore the - sign), equals 2 pi f t, there f is the frequency.
Therefore 2 pi f = 4
f = 2/pi
and P = 1/f = pi/2