If $[x]$ denotes the greatest integer not exceeding the number $x$, then $f(x)$ defined by…

If $[x]$ denotes the greatest integer not exceeding the number $x$, then $f(x)$ defined by $f(x)=\left\{\begin{array}{ll}{[x],} & \text { if } x < 2 \\ {[x]-1,} & \text { if } x \geq 2\end{array}\right.$ is continuous in the interval.
  1. $[1,2) \cup(2,3)$
  2. $[1,3)$
  3. $(1,3)$
  4. $R$

Solution

Given function, $ \begin{aligned} & \qquad f(x)=\left\{\begin{aligned} {[x], } & \text { if } x < 2 \\ {[x]-1, } & \text { if } x \geq 2 \end{aligned}\right. \\ & \text { At } \quad x=2, f(2)=1 \\ & \text { LHL } \\ & \qquad(\text { at } x=2)=\lim _{h \rightarrow 0}[2-h]=1 \\ & \text { and RHL (at } x=2)=\lim _{h \rightarrow 0}([2+h]-1)=2-1=1 \end{aligned} $ So, $f(x)$ is continuous at $x=2$ And $[x]$ is continuous in $[n, n+1), \forall n \in$ integer. So, given function continuous in the interval $[1,3)$

Asked in: AP EAMCET 2018 (23 Apr Shift 2)

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