1. This part consists of 3 short-answer questions. You should write down the steps of your argument. (a) (3 points) Find dy da and day. The. For which values of t is the curve concave upward? =t'+1, y=e -1. (b) (3 points) What is the relation between two lines L1 : 7 = (1, 1, 2) + t(-1, 1, -2) and L2 : F = (0, 3, 2) + s (1, 0, 2)? (c) (3 points) For what values of b are the vectors (b, 1, 5) and (6, b+ 1, b4 -1) parallel