The greatest integer function f : R → R given by f(x) =[x] is :

The correct answer is Option (4) → neither one-one nor onto

$f:[x]$    $f(x)=[x]$

for $f(x)∈R-Z$   (No x in R exist)

⇒ Not ONTO

$f(2,1)=f(2,2)=2$   (Not one-one)