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The function f(x)=(x) where (x) denotes the smallest integer `ge x` isA. everywhere continuousB. continuous at x=n, `n in Z`C. continuous on R-ZD. none of these

Answer» Correct Answer - C
For any `n in Z`, we have
`("LHL at x=n")=underse(x to n^(-))lim f(x)`
`Rightarrow ("LHL at x=n")=underse(h to 0)lim f(n-h)=underset(h to 0)lim (n-h)=n`
`("RHL at x=n")=underset(x to n^(+))lim f(x)`
`Rightarrow ("RHL at x=n")=underset(h to 0)lim f(n+h)=n+1`
`therefore underset(x to n^(-))lim f(x)ne underset(x to n^(+))lim f(x)`
Let `x=a in R-Z`. Then, there exists `n in Z` such that `n lt a lt n+1` Now,
`underset(x to a^(-))lim f(x)=underset(x to 0)limf(a-h)=underset(h to 0)lim (a-h)=n+1`
`underset(x to a^(+))lim f(x)=underset(h to 0)limf(a+h)=underset(h to 0)lim (a+h)=n+1`
`and, f(a)=n+1`
`therefore underset(x to a^(-))lim f(x)=underset(x to a^(+))lim f(x)=f(a)`
There f(x) is a continuous at x=a
Hence, f(x) is a continous at all points other than integer points.


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