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Question: Answered & Verified by Expert
If $\mathrm{f}(\mathrm{x})=[\mathrm{x}]$, for $\mathrm{x} \in(-1,2)$, then $\mathrm{f}$ is discontinuous at (where $[\mathrm{x}]$ represents floor function)
MathematicsFunctionsMHT CETMHT CET 2021 (20 Sep Shift 1)
Options:
  • A $\mathrm{x}=-1,0,1,2$
  • B $\mathrm{x}=-1,0,1$
  • C $\mathrm{x}=0,1$
  • D $\mathrm{x}=2$
Solution:
1168 Upvotes Verified Answer
The correct answer is: $\mathrm{x}=0,1$
We have $\mathrm{f}(\mathrm{x})=[\mathrm{x}]$
Let $[\mathrm{x}]=\mathrm{K}$, an integer.
$$
\therefore \lim _{x \rightarrow K^{+}} f(x)=K \text { and } \lim _{x \rightarrow K^{-}} f(x)=K-1
$$
Thus given function is not continuous at all integral values in its domain.
$\because \mathrm{f}$ is discontinuous at $\mathrm{x}=0,1$.

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