A study showed that the ratio of the probability that consumers choose brand A over brand B can be given by

where a is the number of features of brand A, b is the number of features of brand B, and c is the number of common features. Show the following.
(a) If a > b > c, then ƒ is increasing and concave upward.
(b) If b > a > c, then ƒ is decreasing and concave downward.

Transcribed Image Text:

f(c) = a - c b- c' с