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The locus of a point whose chord of contact with respect to the circle `x^2+y^2=4`is a tangent to the hyperbola `x y=1`is a/anellipse(b) circlehyperbola (d) parabolaA. ellipseB. circleC. hyperbolaD. parabola |
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Answer» Correct Answer - C Let the point be (h, k). Then the equation of the chord of contact is `hx+ky=4.` Since `hx+ky=4` is tangent to xy = 1, `x((4-hx)/(k))=1` has two equal roots. Therefore, discriminant of `hx^(2)-4x+k=0` is 0. `therefore" "hk=4` Thus, the locus of (h, k) is xy = 4. |
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