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10. The chords of contact of the pair of tangents drawn from each point on the line 2x + y = 4 to the circle x 2 +y 2 = 1 pass through a fixed point- (a) (2,4) (b) (-1/2,-1/4) (c) (1/2, 1/4) (d) (-2, -4)



10.    The chords of contact of the pair of tangents drawn from each point on the line 2x + y = 4 to the circle x2+y2 = 1 pass through a fixed point-


        (a)    (2,4)


(b)    (-1/2,-1/4)


(c)    (1/2, 1/4)


(d)    (-2, -4)


Grade:upto college level

1 Answers

Jitender Singh IIT Delhi
askIITians Faculty 158 Points
9 years ago
Ans: ©. (1/2, 1/4)
Sol:
Let (h, k) be the point on the line from where pair of tangents are drawn.
Equation of chord of contact:
hx+ky=1
Also (h, k) lie on the line, we have
2h+k=4
hx+(4-2h)y=4
Only (1/2, 1/4) satisfying this equation.
Thanks & Regards
Jitender Singh
IIT Delhi
askIITians Faculty

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