1.

let `f:R->R` be given by `f(x)=[x]^2+[x+1]-3,` where `[x]` denotes the greatest integer less than or equal to `x.` Then, `f(x)` isA. many-one and ontoB. many-one and intoC. one-one and intoD. one-one and onto

Answer» Correct Answer - B
We have
`f(x)=[x]^(2)+[x+1]-3`
`Rightarrow f(x)=[x]^(2)+[x]+1-3 [therefore [x+n]=[x]+n, "where n "in Z]`
`Rightarrow f(x)=[x]^(2)+[x]-2`
`Rightarrow f(x)=([x]+2) ([x]-1)`
Clearly, f(x)=0 for all `x in [1,2] uu [-2, -1]`
So, f is a many-one function.
Also, f(x) assumes only integral values.
`therefore "Range of f" ne R`.
Hence, f(x) is a many-one into function.


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