2. let v = c2(r, r) be the collection of functions f : r + r for which f, f', f" are continuous. let u = {f ev: f" + f = 0}. (a) show that u sv. carefully explain your answer. (b) find two functions fı, f2 € u such that s = {f1, f2} is linearly independent.

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?