JEE MATHEMATICS MCQ: FUNCTIONS

1 Easy

1 of 1

Analyzing +4 | -1

If a function

f\;:\left[ {2,\;\infty } \right) \to B

defined by

f\left( x \right) = {x^2} - 4\;x + 5

is a bijection, then

B =

View answer and explanation

Correct option: B

\left[ {1,\;\infty } \right)

Option B is correct. Since f is a bijection, B must be the range of f. Completing the square,

f(x) = (x-2)^2 + 1

. For

x \in [2, \infty)

, the range is

[1, \infty)

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