Let f:[2,∞) → R be the function defined f(x) = x2 - 4x + 5 , then the range of f is

Question

Let f:[2,∞) → R be the function defined f(x) = x2 - 4x + 5 , then the range of f is (A) (-∞, ∞) (B) [1, ∞) (C) (1, ∞) (D) [5, ∞)

Tardigrade Admin · Accepted Answer

f(x)=(x-2)2+1 ≥ 1, ∀ x ∈[2, ∞) f min =1 at x=2 ∴ Range of f is [1, ∞)

Q. Let $f : [2, \infty) \to R$ be the function defined $f (x) = x^{2} - 4 x + 5$ , then the range of f is