Question:

If $f : R - \{2\} \to R$ is a function defined by $f(x) = \frac{x^2 - 4}{x - 2}$ , then its range is

Updated On: Feb 1, 2025
  • R
  • R - {2}
  • R - {4}
  • R - {-2, 2}
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The Correct Option is C

Approach Solution - 1

We have,
$f(x)=\frac{x^{2}-4}{x-2}, x \neq 2 $
$f(x)=\frac{(x+2)(x-2)}{x-2}, x \neq 2 $
$f(x)=(x+2), x \neq 2$
$\therefore$ Range of $f(x)=R-\{4\}$
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Approach Solution -2

Given:
\(f(x) = \frac{x^2 - 4}{x - 2}\)

\(f(x) = \frac{(x - 2)(x + 2)}{x - 2}\)
For \(x \neq 2\), this simplifies to:
\(f(x) = x + 2\)

Finding the Range:
The simplified function \(f(x) = x + 2\) can take any real value except at x = 2. When x = 2, the original function is undefined, so \(f(x)\) cannot be 4.

Therefore, the range of f(x) is all real numbers except 4:
\(\text{Range of } f(x) = \mathbb{R} - \{4\}\)

So, the correct option is (C): \(\mathbb{R} - \{4\}\)

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Concepts Used:

Functions

A function is a relation between a set of inputs and a set of permissible outputs with the property that each input is related to exactly one output. Let A & B be any two non-empty sets, mapping from A to B will be a function only when every element in set A has one end only one image in set B.

Kinds of Functions

The different types of functions are - 

One to One Function: When elements of set A have a separate component of set B, we can determine that it is a one-to-one function. Besides, you can also call it injective.

Many to One Function: As the name suggests, here more than two elements in set A are mapped with one element in set B.

Moreover, if it happens that all the elements in set B have pre-images in set A, it is called an onto function or surjective function.

Also, if a function is both one-to-one and onto function, it is known as a bijective. This means, that all the elements of A are mapped with separate elements in B, and A holds a pre-image of elements of B.

Read More: Relations and Functions