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Question: Answered & Verified by Expert
Let $[x]$ denote the greatest integer $\leq x$. If $f(x)=$ $[\mathrm{x}]$ and $g(x)=|x|,$ then the value of $\mathrm{f}\left(\mathrm{g}\left(\frac{8}{5}\right)\right)-\mathrm{g}\left(\mathrm{f}\left(-\frac{8}{5}\right)\right)$ is
MathematicsFunctionsBITSATBITSAT 2020
Options:
  • A 2
  • B -2
  • C 1
  • D -1
Solution:
1331 Upvotes Verified Answer
The correct answer is: -1
$\begin{aligned}

&\text { Given that, } f(x)=[x] \text { and } g(x)=|x|\\

&\text { Now, } \mathrm{f}\left(\mathrm{g}\left(\frac{8}{5}\right)\right)=\mathrm{g}\left(\frac{8}{5}\right)=\left[\frac{8}{5}\right]=1

\end{aligned}$

and $\mathrm{g}\left(\mathrm{f}\left(-\frac{8}{5}\right)\right)=\mathrm{g}\left(\left[-\frac{8}{5}\right]\right)=\mathrm{g}(-2)=|-2|=2$

$\therefore \mathrm{f}\left(\mathrm{g}\left(\frac{8}{5}\right)\right)-\mathrm{g}\left(\mathrm{f}\left(-\frac{8}{5}\right)\right)=1-2=-1$

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