A function f is even if and only if when- ever the point(x, y)is on the graph off then point(—x,y)is also on the graph.Algebrai- cally,we define an even function as follows: A function f is even if for every number x in its domain the number—x is also in the do- main and A function f is even if and only if when-ever the point(x, y)is on the graph off then point(-x,y)is also on the graph.Algebrai- cally, we define an even function as follows: A function f is even if for every number x in its domain the number—x is also in the do- main and