A light ray gets reflected from x=−2. If the reflected ray touches the circle x2+y2=4 and point of incident is (−2,−4), then equation of incident ray is
A
4y+3x+22=0
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B
3y+4x+20=0
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C
4y+2x+20=0
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D
y+x+6=0
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Solution
The correct option is A4y+3x+22=0 Let the slope of the reflected ray be m. As it passes through (−2,−4) the equation becomes mx−y=−2m+4 The distance of the tangent line from origin is equal to radius . ⇒|2m+4|√m2+1=2 [condition for the ray of light touching the circle ] ⇒m=−34 Now the equation becomes y+4=−34(x+2) ⇒4y+3x+22=0