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A ray of light passing through the point \mathrm{P}(2,3)  reflects on the x-axis at point \mathrm{A} and the reflected ray passes through the point \mathrm{Q(5,4)}. Let \mathrm{R } be the point that divides the line segment \mathrm{AQ} internally into the ratio \mathrm{2:1} . Let the co-ordinates of the foot of the perpendicular \mathrm{M} from \mathrm{R} on the bisector of the angle \mathrm{P A Q}  be \mathrm{(\alpha, \beta)}. Then, the value of \mathrm{7\alpha+3\beta} is equal to _____.

Option: 1

31


Option: 2

-


Option: 3

-


Option: 4

-


Answers (1)

best_answer


\mathrm{{p}'} be reflection of p about x-axis

\mathrm{Slope\: of \; {p}'Q\:\; \; ^{m}{p}'_{Q}= \, ^{m}A_{Q}= \frac{4+3}{5-2}= \frac{7}{3}.}
\mathrm{\Rightarrow AQ:y-4= \frac{7}{3}\left ( x-5 \right )\quad y= 0\Rightarrow x= \frac{-12}{7}+5= \frac{23}{7}}.



So Coordinates of \mathrm{M:\left ( \frac{23}{7},\frac{8}{3} \right )= \left ( \alpha ,\beta \right )}

\mathrm{\Rightarrow 7\alpha +3\beta = 23+8= 31.}

Posted by

Ritika Kankaria

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