MCQ
The signum function, $f: R \rightarrow R$ is given by $f(x)=\left\{\begin{array}{ll}1, & x>0 \\ 0, & x=0 \\ -1, & x<0\end{array}\right.$ is
- AOne$-$one
- BOnto
- CBijective
- ✓None of these
✓
Answer
Correct option: D.
None of these
We have, $f(1)=f(2)$
$=f(3)=1, f(0)=0$
$f(-1)=f(-2)=f(-3)=-1$
Hence, function $f$ is not one$-$one.
$=f(3)=1, f(0)=0$
$f(-1)=f(-2)=f(-3)=-1$
Hence, function $f$ is not one$-$one.
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