First answer is wrong: a one to one function maps different inputs to different outputs, while you can see that all numbers in [tex] [n,n+1) [/tex] are mapped to the same value [tex] n [/tex], for every [tex] n \in \mathbb{N} [/tex]. So, the function is not one to one.
The second is true: by definition, for all real numbers, x, the greatest integer function returns the largest integer less than or equal to x. This is exactly what is happened with the graph.
The third is true: the greatest integer less than 0.6 is 0.
The fourth is true for the same reason: greatest integer less than 5.1 is 5.
The fifth is false: -3 is actually greater than -3.2, so we have [tex] f(-3.2)=-4 [/tex]
