(s) The range of cos(x) is [-1,1]. A. True. B. False. (t) The graph of an even function is symmetric with respect to the y-axis. A. False. B. True. (u) Given θ = 72°, then its reference angle θ' equals to A. -72° B. 72°
C. 288°
D. 108°
E. None of the above