Question

If f is a real function satisfying f(x+1/x)=x²+1/x² for all x ∈ R – {0}, then write the expression for f(x).

Answer 1

f(x+1/x) = x²+1/x²

For x to be real,

y² - 4 ≥ 0

y ∈(-∞,2]∪[2,∞) 

|y|>2 Ans.