5. f : R. - R. is defined by = x-. Find: a) f-'(([}, 1])) = b) f (f-'(1}, 1])) =III. 1. Give an example of f : R - R, continuous everywhere except at r = 1 and r = 2. 2. Are the following three vectors in R3 linearly independent or not? Ex- plain. a) (2, 1, 0), (0, 2, 1), (1, 0, 2)? b) (-1, 1, 0), (0, -1, 1), (1, 0, -1)? 3. What is a convex set in R2? Give an example of a non-convex set. 4. What is a concave (or: "concave down" ) function from R to R? Give an example of a concave function f : [0, 1] - R