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Mathematics · 2023 · 2 marks
CBSE 2023 · Region 1 · Set 1 · Q21
(a) A function f: A → B defined as f ( x )=2 x is both one-one and onto. If A ={1,2,3,4}, then find the set B.
(a)
A function $\displaystyle \mathrm{f}: \mathrm{A} \rightarrow \mathrm{B}$ defined as $\displaystyle \mathrm{f}(\mathrm{x})=2 \mathrm{x}$ is both one-one and onto. If $\displaystyle \mathrm{A}=\{1,2,3,4\}$, then find the set B .
OR
(b)
Evaluate : \[\sin ^{-1}\left(\sin \frac{3 \pi}{4}\right)+\cos ^{-1}\left(\cos \frac{3 \pi}{4}\right)+\tan ^{-1} \]
Marking-scheme solution
(a)
$\displaystyle \mathrm{f}(1)=2, \mathrm{f}(2)=4, \mathrm{f}(3)=6, \mathrm{f}(4)=8$
$$\therefore \mathrm{B}={$\displaystyle 2,4,6,8$}
OR
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