Question

The domain of the function f (x) = log₂ (log₃ (log₄ x)) is 

(a) (– ∞, 4) 

(b) (0, 4) 

(c) (4, ∞) 

(d) (1, ∞)

Answer 1

Answer: (c) (4, ∞) 

f (x) = log₂ (log₃ (log₄x)) is defined if log₃ (log₄ x) > 0 

⇒ log₄x > 3⁰ 

⇒ log₄ x > 1 

⇒ x > 4¹ = 4  

∴  Domain of the given function is (4, ∞)