1.Relation and Function
hard

The range of the function $f(x) = \frac{x}{{1 + \left| x \right|}},\,x \in R,$ is

A

$R$

B

$(-1,1)$

C

$R-\{0\}$

D

$[-1,1]$

(AIEEE-2012)

Solution

$f\left( x \right) = \frac{x}{{1 + \left| x \right|}},x \in R$

If $x > 0,\left| x \right| = x \Rightarrow f\left( x \right) = \frac{x}{{1 + x}}$

which is not defined for $x=-1$

If $x < 0,\left| x \right| =  – x \Rightarrow f\left( x \right) = \frac{x}{{1 – x}}$

which is not defined for $x=1$

Thus $f\left( x \right)$ defined for all value of $R$ except $1$ and $-1$ 

Hence, range $=(-1,1)$.

Standard 12
Mathematics

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