Consider the following lists. \(\begin{array}{ll} \text { List I } & \text { List II } \\ \hline \text { (A)…

Consider the following lists. \(\begin{array}{ll} \text { List I } & \text { List II } \\ \hline \text { (A) } f(x)=\frac{|x+2|}{x+2}, x \neq-2 & \text { 1. }\left[\frac{1}{3}, 1\right] \\ \hline \text { (B) } g(x)=\mid[x \mid x \in R & \text { 2. } Z \\ \hline \text { (C) } h(x)=|x-[x]|, x \in R & \text { 3. } W \\ \hline \text { (D) } f(x)=\frac{1}{2-\sin 3 x}, x \in R & \text { 4. }[0,1) \\ \hline & \text { 5. }\{-1,1\} \end{array}\)
  1. \(\begin{array}{llll}A & B & C & D \\ 5 & 3 & 2 & 1\end{array}\)
  2. \(\begin{array}{llll}A & B & C & D \\ 3 & 2 & 4 & 1\end{array}\)
  3. \(\begin{array}{llll}A & B & C & D \\ 5 & 3 & 4 & 1\end{array}\)
  4. \(\begin{array}{llll}A & B & C & D \\ 1 & 2 & 3 & 4\end{array}\)

Solution

\(\begin{aligned} (\mathrm{A}) \because f(x) & =\frac{|x+2|}{x+2}, x \neq-2 \\ & =\left\{\begin{array}{ll} \frac{x+2}{x+2}, & x > -2 \\ -\frac{x+2}{x+2}, & x < -2 \end{array}= \begin{cases}1, & x > -2 \\ -1, & x < -2\end{cases} \right. \end{aligned}\) So, range of \(f(x)\) is \(\{-1,1\}\). (B) \(\because\) \(g(x)=|[x]|, x \in R\) As \([x] \in I \Rightarrow|[x]| \in W\) So, range of \(g(x)\) is \(W\). (C) \(\begin{aligned} & \because h(x)=|x-[x]|, x \in R=|\{x\}| \in[0,1) \\ & {[\because\{x\}=x-[x] \text { and }\{x\} \in[0,1)]} \end{aligned}\) So, range of \(h(x)\) is \([0,1)\). \(\begin{array}{lrl} \text { (D) } \because f(x)= & \frac{1}{2-\sin 3 x}, x \in R \\ \because & & -1 \leq \sin 3 x \leq 1, \forall x \in R \\ \Rightarrow & -1 \leq-\sin 3 x \leq 1 \\ \Rightarrow & 2-1 \leq 2-\sin 3 x \leq 2+1 \\ \Rightarrow & \frac{1}{3} \leq \frac{1}{2-\sin 3 x} \leq \frac{1}{1} \end{array}\) So, range of \(f(x)\) is \(\left[\frac{1}{3}, 1\right]\). Hence, option (3) is correct.

Asked in: AP EAMCET 2019 (20 Apr Shift 1)

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