Example 15 Find the maximum and minimum values
of  f , if any, of the function given by f(x) = |x|, x ∈ R Solution From the graph of the given function
(Fig 6 9) , note that
f (x) ≥ 0, for all x ∈ R and  f (x) = 0  if  x = 0 Therefore, the function f has a minimum value 0
and the point of minimum value of f is x = 0