Question 1. Consider the following utility functions ul(x, y) = 2x0.620.4 u2(x, y) = 2 (min {2x, y} ) 0.5 us(x, y) = (2x + y)2 us(x, y) = exp { xy's us(x, y) = (exp {x} )2 exp {y } -1 us(x, y) = 3 Inx + 21ny (a) Group the utility functions according to which are consistent with the same preference orderings. (b) Show which of up and us are concave. For each that is not concave, find a utility function consistent with the same set of preferences that is concave