17. Sheryl is riding on a teeter-totter. Suppose # is the measure of the angle between the ground and Sheryl's highest point on the teeter-totter, and suppose the bar between Sheryl and the pivot has slope m = 2.8 when Sheryl is at the highest point. Which of the following statements is true? (a) tan(0) = 2.8 (b) tan (2.8) = 0 (c) sin(#) = -2.8 (d) cos(8) = -1 (e) cos(#) = 2.8 18. At practice one afternoon, Jan ran seven laps on a one-half mile track at a constant speed of three miles per hour. Which of the following is a constant quantity in this situation? (a) the speed in miles per hour that Jan ran (b) the total number of laps that Jan ran (c) the total time that Jan ran (d) the total hours required to run one lap (e) all of the above 19. Suppose that a > 0. If we know that b = a", then we also know that (a) b = log.(c) (b) c = logs(a) (c) a = log (b) (d) b = log (a) (e) c = loga(b) 20. Let u be the radian or degree measure of an angle. Assuming all factors are defined, which of the following expressions is equal to sin (u) csc(u) sec- (u) + tan (u) (a) cot(u) (b) 2 tan- (u) (c) 2 csc(u) + tan(u) (d) tan? (u) (e) sec-(u)