f (x) = root (x)
 For this case what you must do is build a table with the values that the function takes when inserting a value of x. 
 We have then:
 x f (x)
 1 1
 4 2
 16 4
 25 5
 36 6
 When you get a sufficient number of points, graph each orderly and see the behavior of the graph.
 Answer:
 The graph looks like in the attached image.