1. It's given the function fix. git : h1|:\\t-- l g} 0 Sketch: the domain 00') off(x,y), the set ofthe points where f{x,y) is null and the set of its singular points. 0 Show that this function has no global maximum nor global minimum over its domain 0 Calculate the limit (in the case it exists) off(x,y) along the direction of the curve girl = {it --"'7II.'*.-*'r :::> U}, as r :. -x 0 Find the maximum and the minimum off(x,y) in the case they exist over the following subsets: :1 : {tiny} e Dill l v'lr l : r; r} B = {lg-r. y] 6 Diff] | r; : VET}