Mark the correct alternative in each of the following: If a function f : [2, ∞) → B defined by f(x) = x 2 – 4x + 5 is a bijection, then B =

Question

Philoid · Accepted Answer

Given that a function f : [2, ∞) → B defined by f(x) = x² – 4x + 5 is a bijection.

Put x = 2 in f(x),

f(x) = 2² – 4× 2 + 5

⇒ f(x=2) = 4 – 8 + 5

⇒ f(x=2) = 1

So, B ϵ [1, ∞)