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MathsHardMulti concept2015 · 10 Apr Online

Q72.If the tangent to the conic, y −6 = x2 at (2, 10) touches the circle, x2 + y2 + 8x −2y = k (for some fixed k ) at a point (α, β); then (α, β) is (1) (−717 , 176 ) (2) (−817 , 172 ) (3) (−617 , 1017 ) (4) (−417 , 171 )

What This Question Tests

This question requires finding the equation of a tangent to a parabola, then using this line's property of being tangent to a circle to find the point of contact on the circle.

Concepts Tested

Equation of tangent to a parabolaCondition for tangency to a circlePoint of contact for tangent to circle

Formulas Used

Tangent to y=ax²+b at (x1,y1) is y-y1 = 2ax1(x-x1)

Distance from center to tangent = radius

Equation of normal at point of contact

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