Mathematics · 2021
JEE Main · 27 July 2021, Shift 2 · Q69
The point P ( a, b ) undergoes the following three transformations successively: (a) reflection about the line y=x. (b) translation through 2 units…
The point $\displaystyle \mathrm{P}(\mathrm{a}, \mathrm{b})$ undergoes the following three transformations successively :
(a)
reflection about the line $\displaystyle y=x$.
(b)
translation through $\displaystyle 2$ units along the positive direction of $\displaystyle x$-axis.
(c)
rotation through angle $\displaystyle \frac{\pi}{4}$ about the origin in the anti-clockwise direction.
If the co-ordinates of the final position of the point P are $\displaystyle \left(-\frac{1}{\sqrt{2}}, \frac{7}{\sqrt{2}}\right)$, then the value of
$\displaystyle 2 \mathrm{a}+\mathrm{b}$ is equal to :
Official answer
(3)
$\displaystyle 9$
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JEE Main 2021 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.