Question

Let $f:R\to R$ be defined by

$f\left(x\right)=\frac{1}{x}\forall x\in R.$ Then $f$ is

• A. onto
• B. bijective
• C. $f$ is not defined
• D. one-one

Answer 1

The correct option is C $f$ is not defined

Check existence of function.

Given: $f:R\to R,f\left(x\right)=\frac{1}{x}$

Put $x=0$

$\Rightarrow f\left(0\right)=\frac{1}{0}=\infty$

So, $f\left(x\right)$ is not defined at $x=0$

But in the question the domain given is $R$
Hence, Option (d) is correct one.