What is the range of the function defined by f(x)=x+2/x

Question

What is the range of the function defined by f(x)=x+2/x :

a) [2,+∞)

b) (-∞,2)∪(2.+∞)

c) (-∞,+∞)

d)( -∞,1)∪(1,+∞)

Answer 1

The range is (-oo, -2sqrt(2)) U (2sqrt(2), oo)